dawn_native: Do debug marker validation at encoding time.

This also adds missing coverage for push/pop debug group in render
bundles. The RenderBundleEncoder didn't validate itself on Finish, so
add a regression test for that too.

The overarching goal with this CL is to do validation at encoding time
which will help produce SyncScopeResourceUsage in the frontend for
dispatch() calls so that they can be reused by the backends.

Bug: dawn:635
Change-Id: Ie5a2d987fda3854b3145ba4b7a34994ea605e820
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/38842
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Auto-Submit: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Stephen White <senorblanco@chromium.org>

src/dawn_native/ComputePassEncoder.cpp

@@ -47,6 +47,10 @@ namespace dawn_native {
 
     void ComputePassEncoder::EndPass() {
         if (mEncodingContext->TryEncode(this, [&](CommandAllocator* allocator) -> MaybeError {
+                if (IsValidationEnabled()) {
+                    DAWN_TRY(ValidateProgrammableEncoderEnd());
+                }
+
                 allocator->Allocate<EndComputePassCmd>(Command::EndComputePass);
 
                 return {};