MIPS: Fix for instanceof-proxies failure.

src/mips64/code-stubs-mips64.cc

Index: src/mips64/code-stubs-mips64.cc
diff --git a/src/mips64/code-stubs-mips64.cc b/src/mips64/code-stubs-mips64.cc
index 9649e420d81c20fdfe8496e87ee94e5ef4add9b1..a913085c893ad3e6df2d8a7b449f18e76a8a4889 100644
--- a/src/mips64/code-stubs-mips64.cc
+++ b/src/mips64/code-stubs-mips64.cc
@@ -1531,6 +1531,9 @@ void InstanceOfStub::Generate(MacroAssembler* masm) {
   // Proxy-case: Call the %HasInPrototypeChain runtime function.
   __ bind(&proxy_case);
   __ Push(object, function_prototype);
+  // Invalidate the instanceof cache.
+  DCHECK(Smi::FromInt(0) == 0);
+  __ StoreRoot(zero_reg, Heap::kInstanceofCacheFunctionRootIndex);
   __ TailCallRuntime(Runtime::kHasInPrototypeChain, 2, 1);
 
   // Slow-case: Call the %InstanceOf runtime function.