Prior to this commit, SocketUtils used System.currentTimeMillis() for
the seed for the java.util.Random instance used internally. The use of
the milliseconds value returned by currentTimeMillis() can lead to
collisions for randomly selected free ports for tests executing in
parallel on the same computer.
This commit therefore switches to System.nanoTime() for the Random seed
used in SocketUtils in an attempt to avoid such collisions for tests
executing in parallel in different JVMs on the same computer.
Closes gh-25321
35582ded0e