[turbofan] add ForTesting to pipeline entry points that are for testing only.

test/cctest/compiler/codegen-tester.h

Index: test/cctest/compiler/codegen-tester.h
diff --git a/test/cctest/compiler/codegen-tester.h b/test/cctest/compiler/codegen-tester.h
index 72d658f367ae6ef072af1e89591a6c9c37aeb16b..283d5339740cc5d53a65b2ce62a3d61cff61774f 100644
--- a/test/cctest/compiler/codegen-tester.h
+++ b/test/cctest/compiler/codegen-tester.h
@@ -68,10 +68,8 @@ class MachineAssemblerTester : public HandleAndZoneScope,
       Schedule* schedule = this->Export();
       CallDescriptor* call_descriptor = this->call_descriptor();
       Graph* graph = this->graph();
-      CompilationInfo info(graph->zone()->isolate(), graph->zone());
-      Linkage linkage(graph->zone(), call_descriptor);
-      Pipeline pipeline(&info);
-      code_ = pipeline.GenerateCodeForMachineGraph(&linkage, graph, schedule);
+      code_ =
+          Pipeline::GenerateCodeForTesting(call_descriptor, graph, schedule);
     }
     return this->code_.ToHandleChecked()->entry();
   }