Reviewed-by: Roberto Raggi

This reverts commit 2a59d2ae.

This reverts commit f4163b8b.

Because apparently, while designing the Objective-C language, somebody
thought it was a world-class idea to allow any white-space between the
'@' character and the subsequent keyword. With this fix, we now
correctly parse:
    @  dynamic
and:
    @
      selector
and:
    @"foo"
     "bar"
    @"mooze"
(This last one is 1 single string split over multiple lines.)
Wonderful, isn't it?

What we (and Clang) do not support, but what GCC supports is something
like:
   @"foo"@@  "bar"  @"mooze"  @@
which is equivalent to @"foobarmooze".

Also removed the (conditional) invoke_token from DeclarationAST and use
the qt_invokable_token to store the Q_INVOKABLE, and fixed the ASTMatch
code generation.

For @synchornized when ObjC is disabled.

It now includes comma expressions, conditionals and assignment
expressions.

doing it in 1.3 as well to avoid possible later conflicts

Fixed semantic check for ObjC fast-enumeration for-loops, then merged it with the semantic check for the foreach.