Move NodeContext from TestingSetup to BasicTestingSetup
Summary:
This will allow for the scheduler to be destructed even for tests that
only use the BasicTestingSetup. This fixes a TSAN lock order inversion
issue when running the reverselock_tests and the scheduler_tests
together.
Extracted from core PR18571.
Test Plan:
./src/test/test_bitcoin -t reverselock_tests,scheduler_tests ninja check
Reviewers: #bitcoin_abc, deadalnix, jasonbcox
Reviewed By: #bitcoin_abc, deadalnix, jasonbcox
Differential Revision: https://reviews.bitcoinabc.org/D6766