[Interpreter] Add support for local context loads and stores.

src/interpreter/interpreter.cc

Index: src/interpreter/interpreter.cc
diff --git a/src/interpreter/interpreter.cc b/src/interpreter/interpreter.cc
index a6e9317e0f03e2d8a3175314f1b258d77be8bae4..de0d68cb3da709900feeedbbdd51ad95576a84a4 100644
--- a/src/interpreter/interpreter.cc
+++ b/src/interpreter/interpreter.cc
@@ -221,6 +221,19 @@ void Interpreter::DoLdaContextSlot(compiler::InterpreterAssembler* assembler) {
 }
 
 
+// StaContextSlot <context> <slot_index>
+//
+// Stores the object in the accumulator into |slot_index| of |context|.
+void Interpreter::DoStaContextSlot(compiler::InterpreterAssembler* assembler) {
+  Node* value = __ GetAccumulator();
+  Node* reg_index = __ BytecodeOperandReg8(0);
+  Node* context = __ LoadRegister(reg_index);
+  Node* slot_index = __ BytecodeOperandIdx8(1);
+  __ StoreContextSlot(context, slot_index, value);
+  __ Dispatch();
+}
+
+
 void Interpreter::DoPropertyLoadIC(Callable ic,
                                    compiler::InterpreterAssembler* assembler) {
   Node* code_target = __ HeapConstant(ic.code());