gdb: remove VALUE_NEXT_FRAME_ID, add value::next_frame_id Remove VALUE_NEXT_FRAME_ID, replace it with a method on struct value. Set `m_location.reg.next_frame_id` directly from value::allocate_register_lazy, which is fine because allocate_register_lazy is a static creation function for struct value. Change-Id: Ic9f0f239c166a88dccfee836f9f51871e67548e6