There were three things wrong with the 'and', 'or', and 'nullish' tests
that I added as part of #2940:
1. They were in the wrong folder (should be
expressions/logical-assignment, not expressions/compound-assignment)
2. The tests for ||= and ??= on readonly accessor properties were
incorrect. These assignments would short-circuit if the getter
returned 1 as it previously did, so PutValue would not throw.
3. The tests for ||= and ??= on private methods were invalid, as a
method always evaluates to true in a boolean context, and is not
nullish, so these would always short-circuit.
I've removed the invalid private method cases, fixed the readonly
accessor cases, and added new templates to test the short-circuit
behaviour as well as the non-short-circuit behaviour.
Closes: #3413