Use a dictionary-mode code cache on the map rather than a dual system.

src/ic/mips/handler-compiler-mips.cc

Index: src/ic/mips/handler-compiler-mips.cc
diff --git a/src/ic/mips/handler-compiler-mips.cc b/src/ic/mips/handler-compiler-mips.cc
index b924bdad786ad8e9f6a6b0d47c4c5c8356093d92..3802f16d9d9b13f1965ece601a089be760db5a07 100644
--- a/src/ic/mips/handler-compiler-mips.cc
+++ b/src/ic/mips/handler-compiler-mips.cc
@@ -737,7 +737,7 @@ Handle<Code> NamedStoreHandlerCompiler::CompileStoreCallback(
   __ TailCallRuntime(Runtime::kStoreCallbackProperty);
 
   // Return the generated code.
-  return GetCode(kind(), Code::FAST, name);
+  return GetCode(kind(), name);
 }
 
 
@@ -778,7 +778,7 @@ Handle<Code> NamedLoadHandlerCompiler::CompileLoadGlobal(
   FrontendFooter(name, &miss);
 
   // Return the generated code.
-  return GetCode(kind(), Code::NORMAL, name);
+  return GetCode(kind(), name);
 }