test: Add the start of a testsuite for damage.

Inspired by the previous bug, build something we can use to write
damage testcases, including testing for the bug.

Signed-off-by: Eric Anholt <eric@anholt.net>
1 job for damage in 1 minute and 33 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Test
passed job #25382

00:01:33