Remove obsolete instruction HOuterContext.

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index 17ded772bc80e05ac54d41aea71f0435a7067039..5cb2e9c206d39a65661882054c74ea137ff24cb9 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -3331,14 +3331,6 @@ void LCodeGen::DoContext(LContext* instr) {
 }
 
 
-void LCodeGen::DoOuterContext(LOuterContext* instr) {
-  Register context = ToRegister(instr->context());
-  Register result = ToRegister(instr->result());
-  __ movp(result,
-          Operand(context, Context::SlotOffset(Context::PREVIOUS_INDEX)));
-}
-
-
 void LCodeGen::DoDeclareGlobals(LDeclareGlobals* instr) {
   ASSERT(ToRegister(instr->context()).is(rsi));
   __ push(rsi);  // The context is the first argument.