Our tests (test/jdk/jdk/incubator/vector) now have a number of issues in their approach to use randomisation:

1. The seed for RNG is taken from a dedicated property, the 'jdk.test.lib.random.seed'. If the property is not set, a default value of 1337 is used. Effectively, that means that by default the tests do always run with the same value, which is unacceptable.

2. I see no reason against using the standard Utils.getRandomInstance (and @key randomness) there.
Superficially, the loopopts/superword/TestAlignVectorFuzzer.java presents a nice example.

3. Many tests create their own ad-hoc RNGs like this:
> int origin = (new java.util.Random()).nextInt(SPECIES.length());
> int part = (new java.util.Random()).nextInt(2);
I suggest to change all those occurrences to use the standard AbstractVectorTest.RAND field. Or Utils.getRandomInstance if the former is not handy enough.