I hate it when bugpoint is all ready to give me a bytecode file, then crashes

in final cleanups.  Then you had to run the whole mess again with
-disable-final-cleanups.

This makes bugpoint run the cleanups in a protected environment so that if
they crash, bugpoint itself doesn't crash.  This makes things much happier,
implements a FIXME, and gets rid of YABPO (yet another bugpoint option).

llvm-svn: 9743