Fix backtrace limit stopping on inline frame

If you have set up a backtrace limit, and the backtrace stops
because of this in an inline frame with arguments, you get an
assertion failure:
```
(gdb) bt
(gdb) set backtrace limit 2
(gdb) bt
C:/src/repos/binutils-gdb.git/gdb/frame.c:3346: internal-error: reinflate: Assertion `m_cached_level >= -1' failed.
```

And if this one is fixed, there is another one as well:
```
(gdb) bt
C:/src/repos/binutils-gdb.git/gdb/dwarf2/loc.c:1160: internal-error: dwarf_expr_reg_to_entry_parameter: Assertion `frame != NULL' failed.
```

The reason for both of them is this kind of loop:
```
  while (get_frame_type (frame) == INLINE_FRAME)
    frame = get_prev_frame (frame);
```
Since get_prev_frame respects the backtrace limit, it will return
NULL, and from there on you can't continue.
This changes these loops to use get_prev_frame_always instead, so
you always get a non-inline frame in the end.

With this backtrace works:
```
(gdb) bt
(gdb)
```

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29865
Approved-By: Andrew Burgess <aburgess@redhat.com>

0 files changed, 0 insertions, 0 deletions