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

src/compiler/pipeline.h

Index: src/compiler/pipeline.h
diff --git a/src/compiler/pipeline.h b/src/compiler/pipeline.h
index 0c0a57b28605a53b39c11a45c43395d15da2191e..222d359861050ce2549bf20a75cd076decaf2122 100644
--- a/src/compiler/pipeline.h
+++ b/src/compiler/pipeline.h
@@ -20,6 +20,7 @@ class RegisterConfiguration;
 namespace compiler {
 
 class CallDescriptor;
+class JSGraph;
 class Graph;
 class InstructionSequence;
 class Schedule;
@@ -32,7 +33,7 @@ class Pipeline : public AllStatic {
 
   // Returns a new compilation job for the WebAssembly compilation info.
   static CompilationJob* NewWasmCompilationJob(
-      CompilationInfo* info, Graph* graph, CallDescriptor* descriptor,
+      CompilationInfo* info, JSGraph* jsgraph, CallDescriptor* descriptor,
       SourcePositionTable* source_positions);
 
   // Run the pipeline on a machine graph and generate code. The {schedule} must