JavaScript parser: don't set token position information again and again

There is no need to set the token position information in the loop
searching for the initial token character, simply do that when we
finally found the token start.

tagmanager/ctags/js.c

@@ -370,11 +370,12 @@ static void readToken (tokenInfo *const token)
 	do
 	{
 		c = fileGetc ();
-		token->lineNumber   = getSourceLineNumber ();
-		token->filePosition = getInputFilePosition ();
 	}
 	while (c == '\t'  ||  c == ' ' ||  c == '\n');
 
+	token->lineNumber   = getSourceLineNumber ();
+	token->filePosition = getInputFilePosition ();
+
 	switch (c)
 	{
 		case EOF: longjmp (Exception, (int)ExceptionEOF);	break;