Improve polymorphic loads on single slots.

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index 79ca5f59e7f663e9f06af2eadf10dd80eae314a1..debc078cbaae9a4b3e53bfbe88a5f6c379812e5c 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -1722,9 +1722,9 @@ LInstruction* LChunkBuilder::DoCheckFunction(HCheckFunction* instr) {
 }
 
 
-LInstruction* LChunkBuilder::DoCheckMap(HCheckMap* instr) {
+LInstruction* LChunkBuilder::DoCheckMaps(HCheckMaps* instr) {
   LOperand* value = UseRegisterAtStart(instr->value());
-  LCheckMap* result = new(zone()) LCheckMap(value);
+  LCheckMaps* result = new(zone()) LCheckMaps(value);
   return AssignEnvironment(result);
 }