[wasm] Add a flag --wasm-opt to test optimizations in the WASM pipeline.

src/compiler/wasm-compiler.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 "src/compiler/wasm-compiler.h"
 
 #include <memory>
 
 #include "src/isolate-inl.h"
 
@@ skipping 3410 matching lines @@
     pipeline_timer.Start();
   }
 
   // Run the compiler pipeline to generate machine code.
   CallDescriptor* descriptor = wasm::ModuleEnv::GetWasmCallDescriptor(
       &compilation_zone_, function_->sig);
   if (jsgraph_->machine()->Is32()) {
     descriptor =
         module_env_->GetI32WasmCallDescriptor(&compilation_zone_, descriptor);
   }
-  job_.reset(Pipeline::NewWasmCompilationJob(&info_, jsgraph_->graph(),
-                                             descriptor, source_positions));
+  job_.reset(Pipeline::NewWasmCompilationJob(&info_, jsgraph_, descriptor,
+                                             source_positions));
   ok_ = job_->ExecuteJob() == CompilationJob::SUCCEEDED;
   // TODO(bradnelson): Improve histogram handling of size_t.
   // TODO(ahaas): The counters are not thread-safe at the moment.
   //    isolate_->counters()->wasm_compile_function_peak_memory_bytes()
   // ->AddSample(
   //        static_cast<int>(jsgraph->graph()->zone()->allocation_size()));
 
   if (FLAG_trace_wasm_decode_time) {
     double pipeline_ms = pipeline_timer.Elapsed().InMillisecondsF();
     PrintF(
@@ skipping 45 matching lines @@
                             function_->code_start_offset),
            compile_ms);
   }
 
   return code;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8