Fix the bugfix in 06094f1b.
krb5pa-md5: Tweak RC4 on GPU, unrolling and working on 32-bits at
a time when possible. Some 50% boost seen here and this should also
make it runnable on devices that can't do byte-addressed stores.
Improved shared LWS test - use unique keys in case it matters for
thread diversion. For krb5pa-md5-opencl this is a 45% boost IRL
while the benchmark gets a hit. Also do a similar thing in local
GWS enumeration of some formats.