Test file locking of SEQUENTIAL, LINE-SEQUENTIAL, RELATIVE

We should add tests for file locking of SEQUENTIAL, LINE-SEQUENTIAL, RELATIVE.
We should add these tests to tests/run.src/miscellaneous.at

We already have tests for file locking of INDEXED files.
https://github.com/opensourcecobol/opensourcecobol4j/blob/develop/tests/indexed-lock.src/file-lock.at