Re-enable test with modifications for Neon vector changes in clang.

I mistakenly thought that this was checking for vector name mangling, but
it is not.  Since we're no longer wrapping Neon vectors in structs, this
test can just return a vector directly.  There are already other tests for
that, so just to make this interesting, change the test to return a struct
of two vectors.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@119434 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGen/arm-vector-arguments.c

@@ -8,9 +8,9 @@
 
 #include <arm_neon.h>
 
-// temporarily skip check: define void @f0(%struct.__simd128_int8_t* sret %agg.result, <16 x i8> %{{.*}}, <16 x i8> %{{.*}})
-int8x16_t f0(int8x16_t a0, int8x16_t a1) {
-  return vzipq_s8(a0, a1).val[0];
+// CHECK: define void @f0(%struct.int8x16x2_t* sret %agg.result, <16 x i8> %{{.*}}, <16 x i8> %{{.*}})
+int8x16x2_t f0(int8x16_t a0, int8x16_t a1) {
+  return vzipq_s8(a0, a1);
 }
 
 // Test direct vector passing.