Simplify invocation sequence at monomorphic function invocation sites.

src/mips/lithium-mips.h

Index: src/mips/lithium-mips.h
diff --git a/src/mips/lithium-mips.h b/src/mips/lithium-mips.h
index 46e9eaff742e52ab046c85d4e11f57796086c5f1..ef8272680257f84da5799d3d78dbcd8c7c91f8cc 100644
--- a/src/mips/lithium-mips.h
+++ b/src/mips/lithium-mips.h
@@ -1453,6 +1453,7 @@ class LInvokeFunction: public LTemplateInstruction<1, 1, 0> {
   virtual void PrintDataTo(StringStream* stream);
 
   int arity() const { return hydrogen()->argument_count() - 1; }
+  Handle<JSFunction> known_function() { return hydrogen()->known_function(); }
 };