[RFA] testsuite/gdb.c++/ref-types.exp: use runto

[Michael Elizabeth Chastain]

Fernando Nasser writes:
> But I wonder if we should not call gdb_start_again() the first time
> around instead of having the code duplicated.  It is exactly the same
> thing.

Doh!  I'm so busy with individual lines, I missed an opportunity to
take out a whole section.

ref_types.exp works now, so I am going to leave it alone and fix more
pressing problems first: like gdb.c++/userdef.exp, which has no code,
and gdb.c++/virtfunc.exp, which XFAILs some tests because gdb doesn't
do the right thing.

Michael