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

src/ic/mips64/handler-compiler-mips64.cc

Index: src/ic/mips64/handler-compiler-mips64.cc
diff --git a/src/ic/mips64/handler-compiler-mips64.cc b/src/ic/mips64/handler-compiler-mips64.cc
index 52260ee754e5b585253e3c63a3039d00d46b3392..55e5eaac32700288a60018a5f936ec4843ba300f 100644
--- a/src/ic/mips64/handler-compiler-mips64.cc
+++ b/src/ic/mips64/handler-compiler-mips64.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);
 }