JDK 9 RFR for 8031980: Add new j.u.l deadlock test for JDK-8027670 and JDK-8029281

[Daniel Fuchs]

Hi,

Please find below a webrev for:

8031980: Add new j.u.l deadlock test for JDK-8027670 and JDK-8029281
https://bugs.openjdk.java.net/browse/JDK-8031980

<http://cr.openjdk.java.net/~dfuchs/webrev_8031980/webrev.00/>

Thread dumps that were sent to me after recent sighting of
JDK-8027670 have allowed me to find a much better test for
verifying the JDK-8029281 fix.

The new test (TestLogConfigurationDeadLockWithConf) is similar to
the old one  (TestLogConfigurationDeadLock) except that it creates
loggers from a configuration which is much more prone to excite
the deadlock.
The new test almost always fail on a platform/build that doesn't have
the fix for JDK-8029281.

best regards,

-- daniel