strub: accept indirection of volatile pointer types [PR118007]

strub: accept indirection of volatile pointer types [PR118007]

We don't want to indirect pointers in strub wrappers, because it
generally isn't profitable, but if the argument is volatile, then we
must use indirection to preserve access patterns, so amend the
assertion check.

for  gcc/ChangeLog

	PR middle-end/118007
	* ipa-strub.cc (pass_ipa_strub::execute): Accept indirecting
	volatile args of pointer types.

for  gcc/testsuite/ChangeLog

	PR middle-end/118007
	* gcc.dg/strub-pr118007.c: New.