log: remove lazy, remove unused interfaces, unexport methods (#28622)

This change 

- Removes interface `log.Format`, 
- Removes method `log.FormatFunc`, 
- unexports `TerminalHandler.TerminalFormat` formatting methods (renamed to `TerminalHandler.format`)
- removes the notion of `log.Lazy` values


The lazy handler was useful in the old log package, since it
could defer the evaluation of costly attributes until later in the
log pipeline: thus, if the logging was done at 'Trace', we could
skip evaluation if logging only was set to 'Info'.

With the move to slog, this way of deferring evaluation is no longer
needed, since slog introduced 'Enabled': the caller can thus do
the evaluate-or-not decision at the callsite, which is much more
straight-forward than dealing with lazy reflect-based evaluation.

Also, lazy evaluation would not work with 'native' slog, as in, these
two statements would be evaluated differently:

```golang
  log.Info("foo", "my lazy", lazyObj)
  slog.Info("foo", "my lazy", lazyObj)
```

cmd/geth/logtestcmd_active.go

@@ -43,6 +43,7 @@ This command is only meant for testing.
 
 type customQuotedStringer struct {
 }
+
 func (c customQuotedStringer) String() string {
 	return "output with 'quotes'"
 }
@@ -80,8 +81,6 @@ func logTest(ctx *cli.Context) error {
 		log.Info("uint64", "18,446,744,073,709,551,615", uint64(math.MaxUint64))
 	}
 	{ // Special characters
-
-
 		log.Info("Special chars in value", "key", "special \r\n\t chars")
 		log.Info("Special chars in key", "special \n\t chars", "value")
 
@@ -103,9 +102,6 @@ func logTest(ctx *cli.Context) error {
 		var c customQuotedStringer
 		log.Info("a custom stringer that emits quoted text", "output", c)
 	}
-	{ // Lazy eval
-		log.Info("Lazy evaluation of value", "key", log.Lazy{Fn: func() interface{} { return "lazy value" }})
-	}
 	{ // Multi-line message
 		log.Info("A message with wonky \U0001F4A9 characters")
 		log.Info("A multiline message \nINFO [10-18|14:11:31.106] with wonky characters \U0001F4A9")
@@ -166,6 +162,10 @@ func logTest(ctx *cli.Context) error {
 	{ // Logging with 'reserved' keys
 		log.Info("Using keys 't', 'lvl', 'time', 'level' and 'msg'", "t", "t", "time", "time", "lvl", "lvl", "level", "level", "msg", "msg")
 	}
+	{ // Logging with wrong attr-value pairs
+		log.Info("Odd pair (1 attr)", "key")
+		log.Info("Odd pair (3 attr)", "key", "value", "key2")
+	}
 	return nil
 }
 

cmd/geth/testdata/logging/logtest-json.txt

@@ -21,7 +21,6 @@
 {"t":"2023-11-22T15:42:00.408197+08:00","lvl":"info","msg":"an error message with quotes","error":"this is an 'error'"}
 {"t":"2023-11-22T15:42:00.408202+08:00","lvl":"info","msg":"Custom Stringer value","2562047h47m16.854s":"2562047h47m16.854s"}
 {"t":"2023-11-22T15:42:00.408208+08:00","lvl":"info","msg":"a custom stringer that emits quoted text","output":"output with 'quotes'"}
-{"t":"2023-11-22T15:42:00.408215+08:00","lvl":"info","msg":"Lazy evaluation of value","key":"lazy value"}
 {"t":"2023-11-22T15:42:00.408219+08:00","lvl":"info","msg":"A message with wonky 💩 characters"}
 {"t":"2023-11-22T15:42:00.408222+08:00","lvl":"info","msg":"A multiline message \nINFO [10-18|14:11:31.106] with wonky characters 💩"}
 {"t":"2023-11-22T15:42:00.408226+08:00","lvl":"info","msg":"A multiline message \nLALA [ZZZZZZZZZZZZZZZZZZ] Actually part of message above"}
@@ -49,3 +48,5 @@
 {"t":"2023-11-22T15:42:00.40835+08:00","lvl":"info","msg":"raw nil","res":null}
 {"t":"2023-11-22T15:42:00.408354+08:00","lvl":"info","msg":"(*uint64)(nil)","res":null}
 {"t":"2023-11-22T15:42:00.408361+08:00","lvl":"info","msg":"Using keys 't', 'lvl', 'time', 'level' and 'msg'","t":"t","time":"time","lvl":"lvl","level":"level","msg":"msg"}
+{"t":"2023-11-29T15:13:00.195655931+01:00","lvl":"info","msg":"Odd pair (1 attr)","key":null,"LOG_ERROR":"Normalized odd number of arguments by adding nil"}
+{"t":"2023-11-29T15:13:00.195681832+01:00","lvl":"info","msg":"Odd pair (3 attr)","key":"value","key2":null,"LOG_ERROR":"Normalized odd number of arguments by adding nil"}

cmd/geth/testdata/logging/logtest-logfmt.txt

@@ -21,7 +21,6 @@ t=xxxx-xx-xxTxx:xx:xx+xxxx lvl=info msg="\x1b[35mColored\x1b[0m[" "\x1b[35mColor
 t=xxxx-xx-xxTxx:xx:xx+xxxx lvl=info msg="an error message with quotes" error="this is an 'error'"
 t=xxxx-xx-xxTxx:xx:xx+xxxx lvl=info msg="Custom Stringer value" 2562047h47m16.854s=2562047h47m16.854s
 t=xxxx-xx-xxTxx:xx:xx+xxxx lvl=info msg="a custom stringer that emits quoted text" output="output with 'quotes'"
-t=xxxx-xx-xxTxx:xx:xx+xxxx lvl=info msg="Lazy evaluation of value" key="lazy value"
 t=xxxx-xx-xxTxx:xx:xx+xxxx lvl=info msg="A message with wonky 💩 characters"
 t=xxxx-xx-xxTxx:xx:xx+xxxx lvl=info msg="A multiline message \nINFO [10-18|14:11:31.106] with wonky characters 💩"
 t=xxxx-xx-xxTxx:xx:xx+xxxx lvl=info msg="A multiline message \nLALA [ZZZZZZZZZZZZZZZZZZ] Actually part of message above"
@@ -49,3 +48,5 @@ t=xxxx-xx-xxTxx:xx:xx+xxxx lvl=info msg=nil-custom-struct res=<nil>
 t=xxxx-xx-xxTxx:xx:xx+xxxx lvl=info msg="raw nil" res=<nil>
 t=xxxx-xx-xxTxx:xx:xx+xxxx lvl=info msg=(*uint64)(nil) res=<nil>
 t=xxxx-xx-xxTxx:xx:xx+xxxx lvl=info msg="Using keys 't', 'lvl', 'time', 'level' and 'msg'" t=t time=time lvl=lvl level=level msg=msg
+t=xxxx-xx-xxTxx:xx:xx+xxxx lvl=info msg="Odd pair (1 attr)" key=<nil> LOG_ERROR="Normalized odd number of arguments by adding nil"
+t=xxxx-xx-xxTxx:xx:xx+xxxx lvl=info msg="Odd pair (3 attr)" key=value key2=<nil> LOG_ERROR="Normalized odd number of arguments by adding nil"

cmd/geth/testdata/logging/logtest-terminal.txt

@@ -21,8 +21,7 @@ INFO [xx-xx|xx:xx:xx.xxx] "\x1b[35mColored\x1b[0m["                "\x1b[35mColo
 INFO [xx-xx|xx:xx:xx.xxx] an error message with quotes             error="this is an 'error'"
 INFO [xx-xx|xx:xx:xx.xxx] Custom Stringer value                    2562047h47m16.854s=2562047h47m16.854s
 INFO [xx-xx|xx:xx:xx.xxx] a custom stringer that emits quoted text output="output with 'quotes'"
-INFO [xx-xx|xx:xx:xx.xxx] Lazy evaluation of value                 key="lazy value"
-INFO [xx-xx|xx:xx:xx.xxx] "A message with wonky 💩 characters" 
+INFO [xx-xx|xx:xx:xx.xxx] "A message with wonky 💩 characters"
 INFO [xx-xx|xx:xx:xx.xxx] "A multiline message \nINFO [10-18|14:11:31.106] with wonky characters 💩" 
 INFO [xx-xx|xx:xx:xx.xxx] A multiline message 
 LALA [ZZZZZZZZZZZZZZZZZZ] Actually part of message above 
@@ -50,3 +49,5 @@ INFO [xx-xx|xx:xx:xx.xxx] nil-custom-struct                        res=<nil>
 INFO [xx-xx|xx:xx:xx.xxx] raw nil                                  res=<nil>
 INFO [xx-xx|xx:xx:xx.xxx] (*uint64)(nil)                           res=<nil>
 INFO [xx-xx|xx:xx:xx.xxx] Using keys 't', 'lvl', 'time', 'level' and 'msg' t=t time=time lvl=lvl level=level msg=msg
+INFO [xx-xx|xx:xx:xx.xxx] Odd pair (1 attr)                        key=<nil>                  LOG_ERROR="Normalized odd number of arguments by adding nil"
+INFO [xx-xx|xx:xx:xx.xxx] Odd pair (3 attr)                        key=value                  key2=<nil> LOG_ERROR="Normalized odd number of arguments by adding nil"