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

src/compiler/wasm-compiler.cc

Index: src/compiler/wasm-compiler.cc
diff --git a/src/compiler/wasm-compiler.cc b/src/compiler/wasm-compiler.cc
index 59c9990e7d7e7e2a6837faf086e4e700bc384d13..d72ac71a6bbbdef92d9a4c1d92435745fd31f7f4 100644
--- a/src/compiler/wasm-compiler.cc
+++ b/src/compiler/wasm-compiler.cc
@@ -3428,8 +3428,8 @@ void WasmCompilationUnit::ExecuteCompilation() {
     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.