MIPS: Fix for instanceof-proxies failure.

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 476f82eaf826bb73d160a815d916939b0e95750d..a66675c61138f242d31fd3a6e953176f2e95e08a 100644
--- a/src/mips/code-stubs-mips.cc
+++ b/src/mips/code-stubs-mips.cc
@@ -1529,6 +1529,9 @@ 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.