Add Support unit tests for ReentrantLock

[paulirwin]

There are tests in Apache Harmony for this.

[paulirwin]

I will take this one once #1119 is merged, since it improves the JSR166TestCase base class.

For posterity, the Apache Harmony tests are here: https://github.com/apache/harmony/blob/trunk/classlib/modules/concurrent/src/test/java/ReentrantLockTest.java

[paulirwin]

@NightOwl888 I briefly looked into this one, and it appears that it already has a few tests enabled from the Harmony tests: https://github.com/apache/lucenenet/blob/master/src/Lucene.Net.Tests/Support/Threading/ReentrantLockTest.cs

Of course a lot of them are commented out because the ReentrantLock class only seems to implement what is minimally needed. I don't know if it's worth the effort to port the entire hierarchy and behavior of ReentrantLock from Harmony, as that would be very complex and time-consuming, especially if we're not using that functionality beyond what it does today. Let me know if you have specific thoughts on anything to do here, or if this can be closed out.

[NightOwl888]

I agree. The tests added in #940 are sufficient. There is no reason to port any more of ReentrantLock.