JSSpecCompiler: Make function arguments parsing much simpler

In a nutshell, when we understand that the expression is a function
call (this happens at '(' after an expression), stop parsing expression
and start parsing function arguments. This makes
`FunctionCallCanonicalizationPass` and the workaround for zero argument
function calls obsolete.

Meta/Lagom/Tools/CodeGenerators/JSSpecCompiler/Parser/TextParser.h

@@ -72,6 +72,7 @@ private:
     TextParseErrorOr<void> expect_eof();
 
     TextParseErrorOr<Tree> parse_record_direct_list_initialization();
+    TextParseErrorOr<Vector<Tree>> parse_function_arguments();
     TextParseErrorOr<Tree> parse_expression();
     TextParseErrorOr<Tree> parse_condition();
     TextParseErrorOr<Tree> parse_return_statement();