MIPS: Add monomorphic CompareNilICs and Crankshaft support

src/mips/code-stubs-mips.cc

Index: src/mips/code-stubs-mips.cc
diff --git a/src/mips/code-stubs-mips.cc b/src/mips/code-stubs-mips.cc
index cc1cf4e9fd9f5c9dc87e825596fb882d8a125fb4..93a40be4752497f803f205b6c90d98949050727c 100644
--- a/src/mips/code-stubs-mips.cc
+++ b/src/mips/code-stubs-mips.cc
@@ -97,6 +97,19 @@ void TransitionElementsKindStub::InitializeInterfaceDescriptor(
 }
 
 
+void CompareNilICStub::InitializeInterfaceDescriptor(
+    Isolate* isolate,
+    CodeStubInterfaceDescriptor* descriptor) {
+  static Register registers[] = { a0 };
+  descriptor->register_param_count_ = 1;
+  descriptor->register_params_ = registers;
+  descriptor->deoptimization_handler_ =
+      FUNCTION_ADDR(CompareNilIC_Miss);
+  descriptor->miss_handler_ =
+      ExternalReference(IC_Utility(IC::kCompareNilIC_Miss), isolate);
+}
+
+
 static void InitializeArrayConstructorDescriptor(Isolate* isolate,
     CodeStubInterfaceDescriptor* descriptor) {
   // register state