Fix path to performance timers

utildir changed from pointing to $CHPL_HOME/util/test to $CHPL_HOME/util.
Performance testing was looking for timers in $CHPL_HOME/util/timers instead of
$CHPL_HOME/util/test/timers. This just updates the timer search path.
Merge pull request #184 from ronawho/fixPerformanceTimersPath

Fix path to performance timers

utildir changed from pointing to $CHPL_HOME/util/test to $CHPL_HOME/util.
Performance testing was looking for timers in $CHPL_HOME/util/timers instead of
$CHPL_HOME/util/test/timers. This just updates the timer search path.