Wouter Klouwen authored Nov 20, 2017 and Brad King committed Dec 04, 2017

This commit continues the refactoring of CTest to adopt std::chrono.
After the last sets of changes that introduced std::chrono::steady_clock
and std::chrono::system_clock respectively, it makes sense to have all
the timeouts be stored as std::chrono::duration.

No functional change intended.