testsuite: fixup pr97521.c and pr96713.c on i686-*

On targets that do not have MXX/SSE enabled by default, pr97521
and pr96713 fail because they emit warnings:

pr97521.c:12:1: warning: MMX vector return without MMX enabled
                changes the ABI [-Wpsabi]
pr97521.c:11:1: note: the ABI for passing parameters with
                16-byte alignment has changed in GCC 4.6
pr97521.c:11:1: warning: SSE vector argument without SSE enabled
                changes the ABI [-Wpsabi]

Add -Wno-psabi to dg-options.

gcc/testsuite/ChangeLog:
	* gcc.target/i386/pr97521.c: Add -Wno-psabi to dg-options.
	* gcc.dg/analyzer/pr96713.c: Likewise.

gcc/testsuite/gcc.dg/analyzer/pr96713.c

+/* { dg-options "-Wno-psabi" } */
 typedef int __attribute__ ((vector_size (8))) V;
 
 void

gcc/testsuite/gcc.target/i386/pr97521.c

 /* { dg-do run } */
-/* { dg-options "-O -mno-sse2" } */
+/* { dg-options "-O -mno-sse2 -Wno-psabi" } */
 
 typedef unsigned char __attribute__ ((__vector_size__ (8))) V;
 typedef unsigned long long __attribute__ ((__vector_size__ (16))) W;