Two test cases in `test-readline-interface` are sensitive to resource
constraints (probably due to `\r` and `\n` not arriving within the
appropriate delay to be treated as a single line ending). Move those
tests to `sequential`.
PR-URL: https://github.com/nodejs/node/pull/14681
Fixes: https://github.com/https://github.com/nodejs/node/issues/14674
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
