gdb: pass non-nullptr frame to gdbarch_value_from_register in address_from_register

gdb: pass non-nullptr frame to gdbarch_value_from_register in address_from_register

address_from_register used to pass null_frame_id to
gdbarch_value_from_register as "this frame"'s id, because it's possible
for it to be called during unwind, when "this frame"'s id is not yet
known.  This create an oddity where those register struct values are
created without a valid next frame id.  I would much prefer for things
to be consistent and have all register struct values to have a valid
next frame id.

Since gdbarch_value_from_register takes a frame_info_ptr now, rather
than a frame_id, we can pass down "this frame", even if it doesn't have
a valid id.  gdbarch_value_from_register implementations can obtain the
next frame from it.

However, it's possible for the "this frame"'s next frame to be an
inline frame, inlined in "this frame", in which case that next frame's
id is also not known.  So, loop until we get to the next non-inline
frame (which is actually the frame where registers for "this frame" are
unwound from).  This is the same thing that we do in
value_of_register_lazy, for the same reason.  A later patch will factor
out this "while next frame is inline" loop to apply it to all register
struct values, so this is somewhat temporary.

Change-Id: If487c82620cc5a4a4ea5807f0a0bad80ab984078