Merge #11599: scripted-diff: Small locking rename

Summary:
190bf62be1214b072513c7fd7e01cc191723967c scripted-diff: Small locking rename (Russell Yanofsky)

Pull request description:

Call sync.h primitives "locks" and "mutexes" instead of "blocks" and "waitable critical sections" to match current coding conventions and c++11 standard names.

This PR does not rename the "CCriticalSection" class (though this could be done as a followup) because it's used everywhere and would swamp the other changes in this PR. Plain mutexes should mostly be preferred instead of recursive mutexes in new code anyway.

Tree-SHA512: 39b5b2be8f7a98227be8ab0648bdbb1b620944659bdc1eb9a15b0fcc0c930457fa0c03170cfedaeee0007ea716c526b31a8d84a86dd2333ce9d8bfabd773fe45

Backport of Core PR11599
https://github.com/bitcoin/bitcoin/pull/11599/files

Test Plan:
make check
test_runner.py

Reviewers: deadalnix, Fabien, #bitcoin_abc, markblundeberg

Reviewed By: Fabien, #bitcoin_abc, markblundeberg

Subscribers: markblundeberg

Differential Revision: https://reviews.bitcoinabc.org/D2996