AsmParser: disallow trailing commas in function call arguments.

test/libsolidity/syntaxTests/inlineAssembly/invalid/empty_fun_arg_beginning.sol

@@ -3,10 +3,9 @@ contract C {
     assembly {
       function f(a, b) {}
       f()
-      f(1,)
       f(,1)
     }
   }
 }
 // ----
-// ParserError: (113-114): Literal, identifier or instruction expected.
+// ParserError: (101-102): Literal, identifier or instruction expected.

test/libsolidity/syntaxTests/inlineAssembly/invalid/empty_fun_arg_end.sol

@@ -0,0 +1,11 @@
+contract C {
+  function f() public pure {
+    assembly {
+      function f(a, b) {}
+      f()
+      f(1,)
+    }
+  }
+}
+// ----
+// ParserError: (103-104): Literal, identifier or instruction expected.

test/libsolidity/syntaxTests/inlineAssembly/invalid/empty_fun_arg_middle.sol

@@ -0,0 +1,10 @@
+contract C {
+  function f() public pure {
+    assembly {
+      function f(a, b, c) {}
+      f(1,,1)
+    }
+  }
+}
+// ----
+// ParserError: (96-97): Literal, identifier or instruction expected.