8023897: Replace/update/rename executeAndCatch in various tests to assertThrows
Reviewed-by: dfuchs, prappo, psandoz, rriggs

8078334: Mark regression tests using randomness
Reviewed-by: xuelei, alanb

8023155: Ensure functional consistency across Random, ThreadLocalRandom, SplittableRandom
Reviewed-by: mduigou
Contributed-by: Doug Lea <dl@cs.oswego.edu>, Paul Sandoz <paul.sandoz@oracle.com>