Due to a bug in MSVC handling of __VA_ARGS__ (see
https://connect.microsoft.com/VisualStudio/feedback/details/380090/variadic-macro-replacement)
wxCALL_FOR_EACH() didn't work correctly as long as more than two arguments
were used with it.
Work around the bug by protecting __VA_ARGS__ from being incorrectly passed as
a single token to the macro being called on every step: this was already done
for wxCALL_FOR_EACH itself with wxCALL_FOR_EACH_, but we need to do it for all
the helper macros too.
Also add a test checking that this does, actually, work.
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77689 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
