Follows I3ea6fb26296f (MySQLPlatformTest):
* Avoid uncertainty and make the code improvable/removable by explaining
what the suppression is for.
* Remove use of outdated AtEase, which hasn't been used in core tests
for several months (ref phpcs.xml), and more generally not in new code
in core or extensions (ref T253461).
Follows I12c17e327628 (FileBackendTest):
* I was going to similarly explain the reason by stating from the linked
task that it is for preg_match, and I was goingn to move the wholesale
suppression to just the getMockForAbstractClass() call that constructs
the FileBackend and thus triggers the issue.
* Instead, I've fixed the constructor to not pass a string there in the first
place as all non-string values are naturally invalid. Even if there is
a way to satisfy the regex with a non-string value that casts to a
valid string, that'd be an invalid value for a FileBackend name as it
pubicly documented as requiring a string, and internally also stored
and typed as assumed to be (after validation) a string.
* Change the valid test cases to be more representative of actually
intended-to-be-valid input, and actually-likely-attempted-but-invalid
input. The regex permits `[a-zA-Z0-9-_]` yet no numbers, capitals
or dashes were validated by the test, and no special characters
rejected by the test.
This follows If29780653 (c250d07bac) from 2019 which added these test
cases to improve code coverage without input from any (admitedly,
non-existent) active maintainers.
Bug: T313663
Change-Id: Ia326e17231a53c7102dcb116817a0c3830c510e4
19dd1a7154