test/tint/builtins/gen: Use returned value

It appears that FXC and DXC do some validation post dead-code-elimination.
These tests have been updated so that the return value is assigned to a storage buffer, ensuring that all validation is performed.

Many DXC tests are affected by https://github.com/microsoft/DirectXShaderCompiler/issues/5082, which have been SKIP'ed.

Fixed: tint:1859
Change-Id: I0001a9a9821846cd0855c3d8ce2bec79ab8e64ef
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/122662
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: James Price <jrprice@google.com>
Commit-Queue: James Price <jrprice@google.com>
Auto-Submit: Ben Clayton <bclayton@google.com>
diff --git a/test/tint/builtins/gen/var/textureDimensions/a4cd56.wgsl.expected.dxc.hlsl b/test/tint/builtins/gen/var/textureDimensions/a4cd56.wgsl.expected.dxc.hlsl
index f8f2b16..085c160 100644
--- a/test/tint/builtins/gen/var/textureDimensions/a4cd56.wgsl.expected.dxc.hlsl
+++ b/test/tint/builtins/gen/var/textureDimensions/a4cd56.wgsl.expected.dxc.hlsl
@@ -1,9 +1,11 @@
 Texture2DArray arg_0 : register(t0, space1);
+RWByteAddressBuffer prevent_dce : register(u0, space2);
 
 void textureDimensions_a4cd56() {
   int3 tint_tmp;
   arg_0.GetDimensions(tint_tmp.x, tint_tmp.y, tint_tmp.z);
   uint2 res = tint_tmp.xy;
+  prevent_dce.Store2(0u, asuint(res));
 }
 
 struct tint_symbol {