There is no more mixed-newline file in the repository after this patch.
Except for`.bat` and `.sln` files (4 in total), all files use LF
newlines.
Also:
- `spacecheck.pl`: drop mixed-EOL exception for test data.
- runtests: add option `-w` to check if test data has stray CR bytes in
them.
- build: enable the option above in test targets, except the CI-specific
one where `spacecheck.pl` does this job already.
- tested OK (with expected failures) in CI with stray CRs added.
- cmake: enable option `-a` for the `tests` target. To continue testing
after a failed test.
Follow-up to 63e9721b63#19313
Follow-up to 6cf3d7b1b1#19318
Follow-up to 4d2a05d3fe#19284Closes#19347