[NFC][PowerPC][clang] Update clang/test/Driver/aix-default-target-triple.c for AIX specific targets (#147584)

This is a followup on the [[PowerPC][clang] Fix triple constructor
ambiguity causing "unknown" target triple on
AIX](#147488 (comment)) to address
the [post-commit review
comment](#147488 (comment)).

---------

Co-authored-by: Tony Varghese <[email protected]>

Author: tonykuttai

clang/test/Driver/aix-default-target-triple.c

@@ -2,12 +2,12 @@
 // This test verifies that the default target triple is correctly resolved
 // and doesn't fall back to "unknown" due to constructor ambiguity.
 
-// REQUIRES: system-aix
+// REQUIRES: system-aix, target={{.*}}-aix{{.*}}
 // RUN: %clang -v %s -c 2>&1 | FileCheck %s --check-prefix=CHECK-TARGET
 
 // Test that the target triple contains AIX and is not "unknown"
 // The target should be something like "powerpc-ibm-aix7.3.0.0"
-// CHECK-TARGET: Target: {{.*}}aix{{.*}}
+// CHECK-TARGET: Target: {{.*}}-aix{{.*}}
 
 int main() {
     return 0;