ipa/120006 - wrong code with IPA PTA

ipa/120006 - wrong code with IPA PTA

When PTA gets support for special-handling more builtins in
find_func_aliases the corresponding code in find_func_clobbers
needs updating as well since for unhandled cases it assumes
the former will populate ESCAPED accordingly.  The following
fixes a few omissions, the testcase runs into the missing strdup
handling.  I believe the more advanced handling using modref
results and fnspecs opened a larger gap, the proper fix is to
merge both functions, gating the clobber/use part on a parameter
to avoid diverging.

	PR ipa/120006
	* tree-ssa-structalias.cc (find_func_clobbers): Handle
	strdup, strndup, realloc, index, strchr, strrchr, memchr,
	strstr, strpbrk builtins like find_func_aliases does.

	* gcc.dg/torture/pr120006.c: New testcase.