testsuite: Fix up pr94482.c testcase [PR94482]

testsuite: Fix up pr94482.c testcase [PR94482]

The test FAILs on powerpc64-linux with -m32 due to psabi warnings.
Furthermore, the test needs really -msse2 to reproduce on x86 -m32 at -O2.

2020-04-11  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/94482
	* gcc.dg/torture/pr94482.c: Add -Wno-psabi -w.  Don't add -msse
	and sse_runtime effective target on x86, instead only add -msse2
	if target is sse2_runtime.