message: Add a convenience getContext() method in OpState to reduce boilerplate on clients.
diff: @@ -106,6 +106,9 @@ public:
  Instruction *getInstruction() const { return state; }
  Instruction *getInstruction() { return state; }
  + /// Return the context this operation belongs to.
  + MLIRContext *getContext() { return getInstruction()->getContext(); }
  +
  /// The source location the operation was defined or derived from.
  Location getLoc() const { return state->getLoc(); }
  