Don't use PL_check[op_type] to check for filetets ops to stack

Don't use PL_check[op_type] to check for filetets ops to stack

This breaks hooking the filetest ops' check function by modules like
bareword::filehandles.  Instead use the OP_IS_FILETEST() macro to decide
check for filetest ops.  Also add an OP_IS_STAT() macro for when we want
to check for (l)stat as well as the filetest ops.

c.f. https://rt.cpan.org/Ticket/Display.html?id=127073