tests: replace remaining CR bytes with the new macro %CR

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 #19284

Closes #19347

docs/runtests.md

@@ -289,6 +289,10 @@ Enable verbose output. Speaks more than by default. If used in conjunction
 with parallel testing, it is difficult to associate the logs with the specific
 test being run.
 
+## `-w`
+
+Verify test data.
+
 ## `-vc \<curl\>`
 
 Provide a path to a custom curl binary to run when verifying that the servers

docs/tests/FILEFORMAT.md

@@ -78,6 +78,10 @@ For example, to insert the word hello 100 times:
 
 ## Whitespace
 
+To force CRLF newline, add this macro to the end of the line:
+
+    %CR  - carriage return
+
 To add significant whitespace characters at the end of the line, or to empty
 lines: