date: fix the strftime O and E modifier leaks #11656

[tobyw21]

This PR fixes date: strftime with O and E modifiers. #11656

Changes

• change regex in coreutils/src/uu/date/src/format_modifiers.rs:82 to %([_OE0^#+-]*)(\d*)(:*[a-zA-Z])
• add tests for O and E modifiers

Limitations

None

Build requirements

Rust stable

Testing

Tested with make test

before

$ LC_ALL=C TZ=UTC target/debug/coreutils date -d '2024-06-15' '+%Om-%Oy-%Ol'
%Om-%Oy-%Ol
$ echo $?
0

after

$ LC_ALL=C TZ=UTC target/debug/coreutils date -d '2024-06-15' '+%Om-%Oy-%Ol'
06-24-12
$ echo $?
0

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/date/resolution (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/pr/bounded-memory (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/tail/symlink (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/date/date-locale-hour (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/tty/tty-eof (passes in this run but fails in the 'main' branch)
Congrats! The gnu test tests/expand/bounded-memory is now passing!
Congrats! The gnu test tests/printf/printf-surprise is now passing!

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/tail/pipe-f2. tests/tail/pipe-f2 is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/tail/retry. tests/tail/retry is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/pr/bounded-memory (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/tty/tty-eof (passes in this run but fails in the 'main' branch)
Note: The gnu test tests/tail/tail-n0f is now being skipped but was previously passing.
Congrats! The gnu test tests/expand/bounded-memory is now passing!
Congrats! The gnu test tests/printf/printf-surprise is now passing!