Changed logging in DoTimed/RunActivity to create less overhead.

- Refactored PerfTimer to use less memory.
- Avoid using the PerfTimer in highly called methods DoTimed and RunActivity, instead tracking long ticks manually to reduce overhead and avoid memory allocations.
- Added some helper methods in PerfTimer to output information when a tick takes too long.
- Changed PerfTimer logging to output the time at the start of the line, and no longer truncate output per line.
- Settings.LongTickThreshold changed from TimeSpan to float and renamed to LongTickThresholdMs.
Merge pull request #5408 from RoosterDragon/perftimer-tick

Changed logging in DoTimed/RunActivity to create less overhead