Fixed VirtualMethod.TestGeneral and VirtualMethod.TestExceptions

Changed the reflection code to be in line with the Java code's
intention.
Fixed TestSetOnce tests

These tests expect exceptions to be thrown, so I added that requirement
as a test attribute.
Fixed TestDoubleBarrelLRUCache.TestThreadCorrectness

Faulty equals() had led to runtime an type error. Time comparison with
current time was incorrectly C#ized.
Fixed TestIOUtils.TestSuppressedExceptions

Rewrote the tests and some of the tested code to work around C# not
having Java's Exception.addSuppressed.
Fixed BaseDocIdSetTestCase.TestAgainstBitSet

Arrays.Fill's exception logic changed to be exactly like Java's
Arrays.fill. Basically, the new logic allows fromIndex to be equal to
toIndex. This change prevents a harmless, but test-breaking exception
from failing this test.
Merge remote-tracking branch 'pradn/fixing-tests'
Minor
Moving ValueSource -> ValueSources to avoid name conflicts
More work on Lucene.Net.Queries
Cleanup