add a simple run_tests.sh to use bash8

this gives a simple way to run against all the files that we'd
want to check with bash8. Currently clocking in at 300+ errors
(no false pos so far that I see).

Change-Id: Idd83b0bf61029b49bb28ad8b6e6261ecbf927555
Merge "add a simple run_tests.sh to use bash8"