gdb/testsuite: tighten up some end-of-line patterns

gdb/testsuite: tighten up some end-of-line patterns

Following on from the previous commit, I searched the testsuite for
places where we did:

  set eol "<some pattern>"

in most cases the <some pattern> could be replaced with "\r\n" though
in the stabs test I've switched to using the multi_line proc as that
seemed like a better choice.

In gdb.ada/info_types.exp I did need to add an extra use of $eol as
the previous pattern would match multiple newlines, and in this one
place we were actually expecting to match multiple newlines.  The
tighter pattern only matches a single newline, so we now need to be
explicit when multiple newlines are expected -- I think this is a good
thing.

All the tests are still passing for me after these changes.

Approved-By: Tom Tromey <tom@tromey.com>