flake8 cleanup of some test files
Minor typo fixes
Minor refactoring of BFPPB for testing

In order to be able to intercept (and block) certain
methods of BFPPB for concurrency testing methods have
been changed to `protected` and an `init()` method has
been introduced to allow a ctor with less logic.
Passing test with intermediate fix

The change (basically to not lock on read) makes
this test pass where before it was failing (when
`Thread.sleep()` was artificially introduced for
calls to releaseLock.

It's unknown if this will be sufficiently safe
going forward.
Merge pull request #1853 from joshmoore/rebased/develop/11709-tile-access

11709 tile access (rebased onto develop)