gdb: Fix assertion failure when inline frame #0 is duplicated

gdb: Fix assertion failure when inline frame #0 is duplicated

Modifying inline-frame-cycle-unwind.exp to use `bt -no-filters` produces
the following incorrect backtrace:

  #0  inline_func () at .../gdb/gdb/testsuite/gdb.base/inline-frame-cycle-unwind.c:49
  #1  normal_func () at .../gdb/gdb/testsuite/gdb.base/inline-frame-cycle-unwind.c:32
  #2  0x000055555555517f in inline_func () at .../gdb/gdb/testsuite/gdb.base/inline-frame-cycle-unwind.c:50
  #3  normal_func () at .../gdb/gdb/testsuite/gdb.base/inline-frame-cycle-unwind.c:32
  Backtrace stopped: previous frame identical to this frame (corrupt stack?)
  (gdb) FAIL: gdb.base/inline-frame-cycle-unwind.exp: cycle at level 1: backtrace when the unwind is broken at frame 1

The expected output, which we get with `bt`, is:

  #0  inline_func () at .../gdb/gdb/testsuite/gdb.base/inline-frame-cycle-unwind.c:49
  #1  normal_func () at .../gdb/gdb/testsuite/gdb.base/inline-frame-cycle-unwind.c:32
  Backtrace stopped: previous frame identical to this frame (corrupt stack?)
  (gdb) PASS: gdb.base/inline-frame-cycle-unwind.exp: cycle at level 1: backtrace when the unwind is broken at frame 1

The cycle checking in `get_prev_frame_maybe_check_cycle` relies on newer
frame ids having already been computed and stashed.  Unlike other
frames, frame #0's id does not get computed immediately.

The test passes with `bt` because when applying python frame filters,
the call to `bootstrap_python_frame_filters` happens to compute the id
of frame #0.  When `get_prev_frame_maybe_check_cycle` later tries to
stash frame #2's id, the cycle is detected.

The test fails with `bt -no-filters` because frame #0's id has not been
stashed by the time `get_prev_frame_maybe_check_cycle` tries to stash
frame #2's id which succeeds and the cycle is only detected later when
trying to stash frame #4's id.  Doing `stepi` after the incorrect
backtrace would then trigger an assertion failure when trying to stash
frame #0's id because it is a duplicate of #2's already stashed id.

In `get_prev_frame_always_1`, if this_frame is inline frame 0, then
compute and stash its frame id before returning the previous frame.
This ensures that the id of inline frame 0 has been stashed before
`get_prev_frame_maybe_check_cycle` is called on older frames.

The test case has been updated to run both `bt` and `bt -no-filters`.

Co-authored-by: Andrew Burgess <aburgess@redhat.com>