Remove non-working and hence unused features from B's OptreeCheck test code.

Remove non-working and hence unused features from B's OptreeCheck test code.

'retry' is no use without 'debug', and 'debug' doesn't work (doesn't enable
regexp debugging output for the retry) because C<use re 'debug'> is lexically
scoped, so can't be applied at runtime after the event to an already compiled
regexp. (And the "obvious" fix of turning it on for compile time isn't working
for some reason, so it's not trivial to fix this unused feature. Version
control will preserve the code if anyone wants to investigate, fix and
resurrect it.)