gdb: make frame_info_ptr grab frame level and id on construction This is the first step of making frame_info_ptr automatic. Remove the frame_info_ptr::prepare_reinflate method, move that code to the constructor. Change-Id: I85cdae3ab1c043c70e2702e7fb38e9a4a8a675d8 Reviewed-By: Bruno Larsen <blarsen@redhat.com>