[turbofan] Enable concurrent (re)compilation.

test/cctest/compiler/test-run-bytecode-graph-builder.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <utility>
 
 #include "src/compiler/pipeline.h"
 #include "src/execution.h"
 #include "src/handles.h"
 #include "src/interpreter/bytecode-array-builder.h"
@@ skipping 111 matching lines @@
     CHECK(function->shared()->HasBytecodeArray());
 
     // TODO(mstarzinger): We should be able to prime CompilationInfo without
     // having to instantiate a ParseInfo first. Fix this!
     ParseInfo parse_info(zone_, function);
 
     CompilationInfo compilation_info(&parse_info, function);
     compilation_info.SetOptimizing();
     compilation_info.MarkAsDeoptimizationEnabled();
     compilation_info.MarkAsOptimizeFromBytecode();
-    compiler::Pipeline pipeline(&compilation_info);
-    Handle<Code> code = pipeline.GenerateCode();
+    Handle<Code> code = Pipeline::GenerateCodeForTesting(&compilation_info);
     function->ReplaceCode(*code);
 
     return function;
   }
 
   DISALLOW_COPY_AND_ASSIGN(BytecodeGraphTester);
 };
 
 
 #define SPACE()
@@ skipping 2788 matching lines @@
 
   BytecodeGraphTester tester(isolate, zone, script.start());
   auto callable = tester.GetCallable<>();
   Handle<Object> return_value = callable().ToHandleChecked();
   CHECK(return_value->SameValue(*snippet.return_value()));
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8