ComputeSharedMemoryTests: Add missing access qualifier

https://gpuweb.github.io/gpuweb/wgsl.html#variables:

> "Variables in the storage storage class and variables with a storage texture type must have an access attribute applied to the store type."

Bug: tint:692
Change-Id: I61774bb6bda9a7d31e3a85c24fcdb6e2fc25e7b1
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/46378
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
diff --git a/src/tests/end2end/ComputeSharedMemoryTests.cpp b/src/tests/end2end/ComputeSharedMemoryTests.cpp
index c78a06e..2d60148 100644
--- a/src/tests/end2end/ComputeSharedMemoryTests.cpp
+++ b/src/tests/end2end/ComputeSharedMemoryTests.cpp
@@ -87,7 +87,7 @@
             x : u32;
         };
 
-        [[group(0), binding(0)]] var<storage> dst : Dst;
+        [[group(0), binding(0)]] var<storage> dst : [[access(write)]] Dst;
         var<workgroup> tmp : u32;
 
         [[stage(compute), workgroup_size(4,4,1)]]