cppgc: Fix compilation error on gcc

After https://crrev.com/c/3301477 compilation with gcc could
fail with the following errors:
```
error: reference to 'MarkingType' is ambiguous
error: reference to 'SweepingType' is ambiguous
```

Change-Id: Idb0f52853d377ec0c0f373f2e908e6c7fa0da914
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3302850Reviewed-by: Omer Katz <omerkatz@chromium.org>
Commit-Queue: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/main@{#78095}

src/heap/cppgc/heap.cc

@@ -84,9 +84,9 @@ Heap::Heap(std::shared_ptr<cppgc::Platform> platform,
       growing_(&gc_invoker_, stats_collector_.get(),
                options.resource_constraints, options.marking_support,
                options.sweeping_support) {
-  CHECK_IMPLIES(options.marking_support != MarkingType::kAtomic,
+  CHECK_IMPLIES(options.marking_support != HeapBase::MarkingType::kAtomic,
                 platform_->GetForegroundTaskRunner());
-  CHECK_IMPLIES(options.sweeping_support != SweepingType::kAtomic,
+  CHECK_IMPLIES(options.sweeping_support != HeapBase::SweepingType::kAtomic,
                 platform_->GetForegroundTaskRunner());
 }