Remove the \b, \f, \v escape sequences from the Scanner

test/libsolidity/semanticTests/strings/string_escapes.sol

@@ -0,0 +1,10 @@
+contract test {
+    function f() public pure returns (bytes32) {
+        bytes32 escapeCharacters = "\t\n\r\'\"\\";
+        return escapeCharacters;
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// f() -> 0x090a0d27225c0000000000000000000000000000000000000000000000000000

test/libsolidity/syntaxTests/string/invalid_legacy_escape.sol

@@ -0,0 +1,8 @@
+contract test {
+    function f() public pure returns (bytes32) {
+        bytes32 escapeCharacters = "\t\b\f";
+        return escapeCharacters;
+    }
+}
+// ----
+// ParserError 8936: (100-105): Invalid escape sequence.

test/libsolidity/syntaxTests/string/string_escapes.sol

@@ -1,6 +1,6 @@
 contract test {
     function f() public pure returns (bytes32) {
-        bytes32 escapeCharacters = "\t\b\n\r\f\'\"\\\b";
+        bytes32 escapeCharacters = "\n\r\'\"\\";
         return escapeCharacters;
     }
 }