Don't mix every http request in with the tests output.
Don't print that the file servers are starting unless
-vv flag is passed.

Capture the output of run with run_output which returns
stdout, stderr and exit_code. Test against this rather
than relying on sys.exit.

tools/format.ts is making CI flaky and it's difficult to run right now.
Reverting to tools/format.py

This reverts commit f19622e7.

Co-authored-by: NGreg Altman <g.s.altman@gmail.com>

Note: findFiles and findFilesWalk are borrowed from the previous
attempt of @pseudo-su (#1434)