Fixed TestLongBitSet.TestPrevSetBit

Used the Java-BitSet versions of BitArray Get and Set. Commented out a
line that was commented out in the original Java source.
Revert "Fixed TestLongBitSet.TestPrevSetBit"

This reverts commit 9b2187e6ff1b27cf60c9d6671d3b8644cc0f8dcb.
Fixed TestLongBitSet.TestPrevBitSet

Used BitSet.SafeGet and Bitset.SafeSet (the methods with Java BitSet
semantics.) Commented out a line that was commented out in the original
Java source.