Cleanup Replication Tests

Remove:

• repl/repl_auth.js – covered in small_oplog_rs

Move:

• repl/repl_options.js -> replsets
• replsets/top.js -> core
• replsets/regex.js -> core
• replsets/gle_explicit_optime.js -> gle
• replsets/get_last_error.js - >gle