CharDriverRewriter - Make two wrappers when Ep1==Ep2
CharDriverRewriter - Make two wrappers when Ep1==Ep2

I wasn't sure if different args should be used when the entry point pair
lists the same entry point (e.g., running write_nvram & write_nvram
concurrently).  This commit makes different wrappers for each call to
the entry point when Ep1==Ep2, and uses different pthread_t,
pthread_create, and pthread_join calls.

This commit DOES NOT use different args for the wrapped entry point,
since I am unsure at this point what args should be the same, and which
ones should be different.  However, I had to do some work on this front,
since when iterating through the entry points, each entry point is only
seen once (so only a single call to pthread_create(write_nvram) would be
created, since we only iterate past write_nvram once).

MontyCarter/chauffeur,MontyCarter/chauffeur