regcomp.c; Use Latin1 \p{} in optimization

regcomp.c; Use Latin1 \p{} in optimization

This commit causes any Latin1-range characters from Unicode properties
to be placed at compile time into the bitmap of the ANYOF node that
implements those properties, and to remove the flag that says they
should be looked for at run time.  This causes the optimizer to generate
a better start class, as it knows more fully which characters can be and
can't be in the start class, and speeds up runtime checking, as it can
just do a bitmap test for these, instead of having to go look at the
swash.