testsuite: Fix up pr84508* tests [PR84508]

testsuite: Fix up pr84508* tests [PR84508]

The tests FAIL on x86_64-linux with
/usr/bin/ld: cannot find -lubsan
collect2: error: ld returned 1 exit status
compiler exited with status 1
FAIL: gcc.target/i386/pr84508-1.c (test for excess errors)
Excess errors:
/usr/bin/ld: cannot find -lubsan

The problem is that only *.dg/ubsan/ubsan.exp calls ubsan_init
which adds the needed search paths to libubsan library.
So, link/run tests for -fsanitize=undefined need to go into
gcc.dg/ubsan/ or g++.dg/ubsan/, even when they are target specific.

2024-05-09  Jakub Jelinek  <jakub@redhat.com>

	PR target/84508
	* gcc.target/i386/pr84508-1.c: Move to ...
	* gcc.dg/ubsan/pr84508-1.c: ... here.  Restrict to i?86/x86_64
	non-ia32 targets.
	* gcc.target/i386/pr84508-2.c: Move to ...
	* gcc.dg/ubsan/pr84508-2.c: ... here.  Restrict to i?86/x86_64
	non-ia32 targets.