Fixup convert-dfp*.c

The testcases use -save-temps which doesn't play nice with -flto
and multilib testing resulting in spurious UNRESOLVED like

/usr/lib64/gcc/x86_64-suse-linux/14/../../../../x86_64-suse-linux/bin/ld: i386:x86-64 architecture of input file `./convert-dfp-2.ltrans0.ltrans.o' is incompatible with i386 output

The following skips the testcases when using -flto.

	* gcc.dg/torture/convert-dfp-2.c: Skip with -flto.
	* gcc.dg/torture/convert-dfp.c: Likewise.

gcc/testsuite/gcc.dg/torture/convert-dfp-2.c

 /* { dg-do run } */
+/* { dg-skip-if "" { *-*-* } { "-flto" } } */
 /* { dg-require-effective-target float16_runtime } */
 /* { dg-require-effective-target dfprt } */
 /* { dg-options "-save-temps" } */

gcc/testsuite/gcc.dg/torture/convert-dfp.c

 /* { dg-do run } */
+/* { dg-skip-if "" { *-*-* } { "-flto" } } */
 /* { dg-require-effective-target float16_runtime } */
 /* { dg-require-effective-target dfprt } */
 /* { dg-options "-save-temps" } */