SERVER-15480 Comment out CursorPointsToSamePlaceRegardlessOfDirection.

This test fails on OS X 10.8 C++11 DEBUG due to an invalid static
cast in both Heap1BtreeImpl::ForwardCursor::pointsToSamePlaceAs and
Heap1BtreeImpl::ReverseCursor::pointsToSamePlaceAs.

Closes #811

Signed-off-by: Benety Goh <benety@mongodb.com>