Part #2:
- row_search_mvcc() should return DB_INTERRUPTED when it got
- Move the sync point from innodb internals to
  handler_rowid_filter_check() where other storage engines can use
  it too
- Add a similar syncpoint for the ICP check.
- Add a bigger test and test coverage for Rowid Filter with MyISAM
- Add test coverage for killed-during-ICP-check scenario