regex: Fix locale regression

regex: Fix locale regression

Things like \S have not been accessible to the synthetic start class
under locale matching rules.  They have been placed there, but the
start class didn't know they were there.

This patch sets ANYOF_CLASS in initializing the synthetic start class
so that downstream code knows it is a charclass_class, and removes
the code that partially allowed this bit to be shared, and which isn't
needed in 5.14, and more thought would have to go into doing it than
was reflected in the code.

I can't come up with a test case that would verify that this works,
because of general locale testing issues, except it looked at a dump of
the generated regex synthetic start class, but the dump isn't the same
thing as the real behavior, and using one is also subject to breakage if
the regex code changes in the slightest.