Revert "Reland: [Compiler] Ensure unoptimized code generation is context independent."

This reverts commit dcd75706.

Reason for revert: Breaks layout tests, blocks roll, see
https://crrev.com/c/1396602; there are wasm CLs in this range too,
but this CL looks like the most likely culprit.

Original change's description:
> Reland: [Compiler] Ensure unoptimized code generation is context independent.
> 
> Now that Asm.js code is also context independent, move code to ensure context independence
> from BytecodeGenerator to FinalizeUnoptimizedCode.
> 
> Reland of CL: https://chromium-review.googlesource.com/c/v8/v8/+/1349236
> 
> Change-Id: I718090850870c61733e0719d4091ec60bc080ebb
> Reviewed-on: https://chromium-review.googlesource.com/c/1396201
> Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
> Reviewed-by: Dan Elphick <delphick@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#58558}

TBR=rmcilroy@chromium.org,delphick@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: I5f547319f31f87777165361747dd42d223fc0b0e
Reviewed-on: https://chromium-review.googlesource.com/c/1396427Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58564}

src/compiler.cc

@@ -569,21 +569,15 @@ bool FinalizeUnoptimizedCode(
     UnoptimizedCompilationJobList* inner_function_jobs) {
   DCHECK(AllowCompilation::IsAllowed(isolate));
 
-  {
-#ifdef DEBUG
-    // Unoptimized compilation should be context-independent. Verify that we
-    // don't access the native context by nulling it out during finalization.
-    SaveContext save(isolate);
-    isolate->set_context(Context());
-#endif
+  // TODO(rmcilroy): Clear native context in debug once AsmJS generates doesn't
+  // rely on accessing native context during finalization.
 
   // Allocate scope infos for the literal.
   DeclarationScope::AllocateScopeInfos(parse_info, isolate);
 
   // Finalize the outer-most function's compilation job.
   if (FinalizeUnoptimizedCompilationJob(outer_function_job, shared_info,
-                                          isolate) !=
-        CompilationJob::SUCCEEDED) {
+                                        isolate) != CompilationJob::SUCCEEDED) {
     return false;
   }
 
@@ -601,7 +595,6 @@ bool FinalizeUnoptimizedCode(
       return false;
     }
   }
-  }
 
   // Report any warnings generated during compilation.
   if (parse_info->pending_error_handler()->has_pending_warnings()) {

src/interpreter/bytecode-generator.cc

@@ -928,6 +928,13 @@ BytecodeGenerator::BytecodeGenerator(
 Handle<BytecodeArray> BytecodeGenerator::FinalizeBytecode(
     Isolate* isolate, Handle<Script> script) {
   DCHECK(ThreadId::Current().Equals(isolate->thread_id()));
+#ifdef DEBUG
+  // Unoptimized compilation should be context-independent. Verify that we don't
+  // access the native context by nulling it out during finalization.
+  SaveContext save(isolate);
+  isolate->set_context(Context());
+#endif
+
   AllocateDeferredConstants(isolate, script);
 
   if (block_coverage_builder_) {