dispatch_sanity: print names of functions that shouldnt be in dispatch table.

dispatch_sanity: print names of functions that shouldnt be in dispatch table.

Previously we just printed the dispatch table index and the user had
to convert it to a function name.  That was a pain because when
FEATURE_remap_table is defined, the assignment of functions to
dispatch table entries is done at run time.

Acked-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>