testsuite: fix AIX testsuite failures

* g++.dg/ext/builtin-shufflevector-2.C: Ignore psabi warning.
	* gcc.dg/uninit-pr93100.c: Skip on AIX.
	* gcc.target/powerpc/pr100085.c: Require int128 and float128.

gcc/testsuite/g++.dg/ext/builtin-shufflevector-2.C

@@ -1,4 +1,5 @@
 // { dg-do compile }
+// { dg-additional-options "-Wno-psabi" }
 
 typedef double v2df __attribute__((vector_size(2 * sizeof (double))));
 

gcc/testsuite/gcc.dg/uninit-pr93100.c

@@ -1,6 +1,7 @@
 /* PR tree-optimization/93100 - gcc -fsanitize=address inhibits -Wuninitialized
    { dg-do compile }
-   { dg-options "-Wall -fsanitize=address" } */
+   { dg-options "-Wall -fsanitize=address" }
+   { dg-skip-if "sanitize address" { "powerpc-ibm-aix*" } } */
 
 struct A
 {

gcc/testsuite/gcc.target/powerpc/pr100085.c

@@ -1,4 +1,6 @@
 /* { dg-do compile } */
+/* { dg-require-effective-target int128 } */
+/* { dg-require-effective-target float128 } */
 /* { dg-options "-O2 -mdejagnu-cpu=power8" } */
 
 typedef __vector unsigned __int128 vui128_t;