- gpperfmon tracks a variety of queries and statistics and system
  properties and metrics in a dedicated database
- Until recently, it hadn't been tested or built very reliably here. It
  is now part of the gpdb_master pipeline.
- We are doing a lot of work to revitalize and provide tests for this
  feature; we plan to make many upcoming pull requests for this
  feature in different ways
- We will look into testing this with installcheck, but for now, it is
  tested with Behave
- Building it as part of PRs will help us get faster feedback
- This should add negligible time to compilation: the tests themselves
  run in less than 5 minutes typically, and will be running in parallel
  with ICW
Signed-off-by: NMarbin Tan <mtan@pivotal.io>