Added tests for finding crash bug conditions.
While owner has a record:
  - 13-drop-table: drop table
  - 14-alter-table: alter table

While owner waits a record:
  - 13-drop-table-while-waiting: drop table

Needs review for 13-drop-table-while-waiting.t before making:
  - 14-alter-table-while-waiting
  - 15-delete-while-waiting

Signed-off-by: Sho Nakatani <lay.sakura@gmail.com>
Merge branch 'crash-test' of github.com:laysakura/q4m into crash-test