[wasm] Inline single-use CompileFailed step

This factors out one part of the "Remove finisher task" CL
(https://crrev.com/c/1400781), which I would like to test in isolation.

R=ahaas@chromium.org

Bug: v8:8423
Change-Id: I7c598f60c4757df8e26508e68da4b3c300a511cb
Reviewed-on: https://chromium-review.googlesource.com/c/1448316Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59256}

src/wasm/module-compiler.cc

@@ -1112,7 +1112,12 @@ class AsyncCompileJob::CompilationStateCallback {
         AsyncCompileJob* job = job_;
         job->foreground_task_runner_->PostTask(
             MakeCancelableTask(job->isolate_, [job] {
-              job->DoSync<CompileFailed, kUseExistingForegroundTask>();
+              HandleScope scope(job->isolate_);
+              SaveContext saved_context(job->isolate_);
+              job->isolate_->set_context(*job->native_context_);
+              WasmError error = Impl(job->native_module_->compilation_state())
+                                    ->GetCompileError();
+              return job->AsyncCompileFailed("Async compilation failed", error);
             }));
 
         break;
@@ -1356,19 +1361,6 @@ class AsyncCompileJob::PrepareAndStartCompile : public CompileStep {
   }
 };
 
-//==========================================================================
-// Step 4b (sync): Compilation failed. Reject Promise.
-//==========================================================================
-class AsyncCompileJob::CompileFailed : public CompileStep {
- public:
-  void RunInForeground(AsyncCompileJob* job) override {
-    TRACE_COMPILE("(4b) Compilation Failed...\n");
-    WasmError error =
-        Impl(job->native_module_->compilation_state())->GetCompileError();
-    return job->AsyncCompileFailed("Async compilation failed", error);
-  }
-};
-
 void AsyncCompileJob::CompileWrappers() {
   // TODO(wasm): Compile all wrappers here, including the start function wrapper
   // and the wrappers for the function table elements.

src/wasm/module-compiler.h

@@ -92,7 +92,6 @@ class AsyncCompileJob {
   class DecodeModule;            // Step 1  (async)
   class DecodeFail;              // Step 1b (sync)
   class PrepareAndStartCompile;  // Step 2  (sync)
-  class CompileFailed;           // Step 4b (sync)
 
   friend class AsyncStreamingProcessor;