CHEF-3863: Return to not trusting the JSON gem at all

Within days of relaxing to a pessmistic constraint on patch release there was
a patch release with breaking changes. We'll have to go back to testing the
latest version by hand again.
11.4.0.rc.0
ensure writes are flushed in run lock IPC
set sync=true on IPC in run lock tests
fix race in test setup

the heart of the test is confirming that the last 2 messages are p1
releasing lock and then p2 acquiring it. The two messages confirm that
the test case is set up correctly.
remove setup message, it's a race either way
Merge branch 'more-runlock-fixes' into 11-stable
CHEF-1292 Lower json stack depth tests to 301

1001 was causing stack level too deep errors on 1.8.7. This is
still a huge stack depth and 1001 was arbitrary.
Release 11.4.0