Changes ./bin/test.sh to pass command line options to pytest, and default to
only running tests in the tests/ directory instead of everywhere excluding
a few directories which is more error-prone.
Also keeps the mock_server used in testing quiet so access log entries don't
appear on stdout.
Rather than by assuming the JSON file we are parsing has junk at the beginning
(which maybe only used to happen?), try parsing it as-is first, and then fall
back to trying again after skipping the first line
Fixes#1347
