Code cleanup - rename 'inline' depth to 'artificial' depth.
* breakpoint.c (set_momentary_breakpoint): Rename at a caller to
frame_id_artificial_p, extend the comment.
* dwarf2-frame-tailcall.c (tailcall_frame_this_id): Rename at a user.
* frame.c (fprint_frame_id): Rename at a user, change debug output
text to "artificial=".
(skip_inlined_frames): Rename to ...
(skip_artificial_frames): ... here. Extend the comment.
(get_stack_frame_id, frame_unwind_caller_id): Rename at a caller.
(frame_id_inlined_p): Rename to ...
(frame_id_artificial_p): ... here. Rename at a user.
(frame_id_eq, frame_id_inner, frame_unwind_caller_pc)
(frame_unwind_caller_pc_if_available, frame_unwind_caller_arch): Rename
at a user.
* frame.h (struct frame_id): Rename inline_depth to artificial_depth.
Extend the comment.
(frame_id_inlined_p): Rename to ...
(frame_id_artificial_p): ... here.
* inline-frame.c (inline_frame_this_id): Rename at a user.
* dwarf2-frame-tailcall.c: Include dwarf2-frame.h.
(dwarf2_tailcall_prev_register_first): Use dwarf2_frame_cfa.
(dwarf2_tailcall_sniffer_first): Remove variable pc_regnum. Replace
gdbarch_pc_regnum and frame_unwind_register_unsigned by
gdbarch_unwind_pc.