gdb: remove the pop_all_targets (and friends) global functions

This commit removes the global functions pop_all_targets,
pop_all_targets_above, and pop_all_targets_at_and_above, and makes
them methods on the inferior class.

As the pop_all_targets functions will unpush each target, which
decrements the targets reference count, it is possible that the target
might be closed.

Right now, closing a target, in some cases, depends on the current
inferior being set correctly, that is, to the inferior from which the
target was popped.

To facilitate this I have used switch_to_inferior_no_thread within the
new methods.  Previously it was the responsibility of the caller to
ensure that the correct inferior was selected.

In a couple of places (event-top.c and top.c) I have been able to
remove a previous switch_to_inferior_no_thread call.

In remote_unpush_target (remote.c) I have left the
switch_to_inferior_no_thread call as it is required for the
generic_mourn_inferior call.

1 files changed, 1 insertions, 2 deletions

diff --git a/gdb/top.c b/gdb/top.c
index 7429978..e0e7e48 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -1855,10 +1855,9 @@ quit_force (int *exit_arg, int from_tty)
      them all out.  */
   for (inferior *inf : all_inferiors ())
     {
-      switch_to_inferior_no_thread (inf);
       try
 	{
-	  pop_all_targets ();
+	  inf->pop_all_targets ();
 	}
       catch (const gdb_exception &ex)
 	{