The FESamplingPruner implements the fault-expansion variance reduction
technique (FE-VRT) as described in: Smith, D. Todd and Johnson, Barry W. and
Andrianos, Nikos and Profeta, III, Joseph A., "A variance-reduction technique
via fault-expansion for fault-coverage estimation" (1997), 366--374.
Change-Id: I04a0c9bb2622974278bd8c73793e51451119e650
