testsuite: Enable pr108308.c test on all int32 targets [PR108308]

This test seems to rely on 32-bit int (and uses a wider constant
which shouldn't fit into int), I've initially enabled it on ilp32+lp64
target, but apparently it works on llp64 too, so I've changed it to
int32.

2023-01-11  Jakub Jelinek  <jakub@redhat.com>

	PR target/108308
	* gcc.dg/pr108308.c: Use int32 target rather than { ilp32 || lp64 }.

gcc/testsuite/gcc.dg/pr108308.c

@@ -1,5 +1,5 @@
 /* PR target/108308 */
-/* { dg-do run { target { ilp32 || lp64 } } } */
+/* { dg-do run { target int32 } } */
 /* { dg-options "-Os -fno-tree-ccp" } */
 
 int a = 1, *d = &a, f = 2766708631, h;