Here are some new tests to test reverse debugging.
I've moved the test solib-reverse (submitted earlier) into this directory.

Since most targets don't (yet) implement reverse debugging,
these tests all return with no results unless you add the
following to your board description file:

     set_board_info gdb,can_reverse 1

In addition, since Process Record requires some special
commands that will not be used by remote debug targets
such as SID and Simics (eg. to start and stop recording),
you'll also want to define the following for process record:

     set_board_info gdb,use_precord 1

I hope that the Virtutech folk will try out these tests
using Simics and let me know if any changes are required.

OK, to commit?