testsuite: Fix up gcc.dg/pr113693.c for ia32

As I wrote earlier and we've discussed on IRC, with the ia32 _BitInt
enablement patch this testcase FAILs on ia32, there is nothing vectorized in
there, even with -mavx512{vl,bw,dq}, so no dbgcnt messages are emitted.

The following patch instead prunes it.

2024-02-12  Jakub Jelinek  <jakub@redhat.com>

	* gcc.dg/pr113693.c: Guard _BitInt(837) use with
	__BITINT_MAXWIDTH__ >= 837.  Use dg-prune-output instead of
	dg-message for dbgcnt message.

gcc/testsuite/gcc.dg/pr113693.c

 /* { dg-do compile { target bitint } } */
 /* { dg-options "-O2 -fdbg-cnt=vect_loop:1" } */
 
+#if __BITINT_MAXWIDTH__ >= 837
 _BitInt(837) g, h;
+#else
+_BitInt(63) g, h;
+#endif
 
 void
 fn1(void)
@@ -10,4 +14,5 @@ fn1(void)
     for (; h; h++)
       ;
 }
-/* { dg-message "dbgcnt" "" { target *-*-* } 0 } */
+
+/* { dg-prune-output "dbgcnt:" } */