Improve handling of property loads on the proto chain.

src/arm/lithium-arm.cc

Index: src/arm/lithium-arm.cc
diff --git a/src/arm/lithium-arm.cc b/src/arm/lithium-arm.cc
index 21c549f175fbbe83c5b1b7e81d2ddba2146f9a11..266a15ac5375b8feee7f824fa005d96c042612a8 100644
--- a/src/arm/lithium-arm.cc
+++ b/src/arm/lithium-arm.cc
@@ -1689,10 +1689,10 @@ LInstruction* LChunkBuilder::DoCheckInstanceType(HCheckInstanceType* instr) {
 
 
 LInstruction* LChunkBuilder::DoCheckPrototypeMaps(HCheckPrototypeMaps* instr) {
-  LOperand* temp1 = TempRegister();
+  LUnallocated* temp1 = TempRegister();
   LOperand* temp2 = TempRegister();
-  LInstruction* result = new(zone()) LCheckPrototypeMaps(temp1, temp2);
-  return AssignEnvironment(result);
+  LCheckPrototypeMaps* result = new(zone()) LCheckPrototypeMaps(temp1, temp2);
+  return AssignEnvironment(Define(result, temp1));
 }