Memory leak reading frame register during inferior event handling

Memory leak reading frame register during inferior event handling

When using a conditional breakpoint where the condition evaluated
to false a large number of times before the program stopped,
a user reported that GDB's memory consumption was growing very
quickly until it ran out of memory.

The problem was tracked down to temporary struct values being created
each time the program stops and handles an inferior event.  Because
the breakpoint condition usually evaluates to false, there can be
a fairly large number of such events to be handled before we eventually
return the prompt to the user (which is when we would normally purge
such values).

This patch fixes the issue by making sure that handle_inferior_event
releases all new values created during its execution.

gdb/ChangeLog:

        * infrun.c (handle_inferior_event_1): Renames handle_inferior_event.
        (handle_inferior_event): New function.