CMake: Calculate Timeout after Regex match
This MR introduces a new feature from CMake 3.6.3 which allows to start the timeout measurement of tests defined via CTest/CMake to only start after a given regular expression has been found.
We use this here to only start measuring once "Running event " has been detected in order to remove possible waiting times from loading libraries via CVMFS from the measurement. This should make the result more accurate.