Fix java.util.Random's constructors.
Subclasses rely on having their overridden setSeed called by Random's
constructors, and the RI actually documents this behavior. (The
documentation even changed between Java 5 and Java 6 to make it _more_
explicit.)
This patch keeps that part of I6239d93bb46876ef1c4a5e155a6dc1ac6fab4eae
that improved our randomness, but reverts the attempt to fix Random's
uncouth behavior.
Also a regression test so we don't try to fix Random again in future.
Bug:
2502231
Change-Id: Ieea1009145c74eac9475c0cd5066dabad20eb114