perf bench futex: Group test parameters cleanup

Do this across all futex-bench tests such that all program parameters
neatly share a common structure, which is nicer than how we have them
now. No changes in program behavior are expected.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lore.kernel.org/lkml/20210809043301.66002-2-dave@stgolabs.net


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>