(hopefully) fix ProcessorCount test

This commit will get overwritten in a minute, it is only here to make git
happy.
Merge topic 'debug-ProcessorCount' into next

64d53ac (hopefully) fix ProcessorCount test
ProcessorCount test: fix path to cmsysTestsCxx executable

Use a generator expression to get the real place of this target instead of
guessing it wrong.
ProcessorCount test: require SystemInformation process to work

Currently this silently fails on some systems. Make sure those things get
noticed so we can fix that.
Merge topic 'debug-ProcessorCount' into next

4d0e2e8 ProcessorCount test: require SystemInformation process to work
e03f83f ProcessorCount test: fix path to cmsysTestsCxx executable