Fix context register allocation in LTransitionElementsKind.

src/ia32/lithium-ia32.cc

Index: src/ia32/lithium-ia32.cc
diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
index 921b5aa933625703838bcfc9caf8cd52065cb2d4..678c0ca70c5bb3edeadf4db931d626f2de0d4442 100644
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -2420,7 +2420,7 @@ LInstruction* LChunkBuilder::DoTransitionElementsKind(
                                             new_map_reg, temp_reg);
     return result;
   } else {
-    LOperand* context = UseRegister(instr->context());
+    LOperand* context = UseFixed(instr->context(), esi);
     LTransitionElementsKind* result =
         new(zone()) LTransitionElementsKind(object, context, NULL, NULL);
     return AssignPointerMap(result);