This fixes PR9664 <http://sourceware.org/bugzilla/show_bug.cgi?id=9664>,
which was a regression I introduced here:

 http://sourceware.org/ml/gdb-patches/2008-09/msg00193.html

The regression is about the fact that the hook-stop in normal_stop
was now being run after frame printing, while it is documented as
being run before.

 "(@samp{hook-stop}) makes the associated commands execute every time
 execution stops in your program: before breakpoint commands are run,
 displays are printed, or the stack frame is printed."

The fix is to put the hook-stop where it was before.  To re-fix
the original issue described in the email pointed above, I moved the
tagging threads as stopped a bit higher up as well.

I've also added a new test so future changes don't miss
this hook-stop-before-print-stack-frame rule.

Tested on x86_64-linux, sync/async, and checked in.

-- 
Pedro Alves