ENH: Reduce test times for Debug builds

Some tests run for extremely long times when built Debug or
RelWithDebInfo.

For these long running tests, reduce the run time by selecting
parameters that trade-off speed and accuracy.

Change-Id: I1749bd5c1000bb9b46340f28c1a2a97035f310ab
Merge topic 'ReduceTestTimes'

e3cf086 ENH: Reduce test times for Debug builds