test: deflakenize test_ddl_drop_table_partial_failure
Summary
- test: deflakenize test_ddl_drop_table_partial_failure
The problem was that we were expecting last raft log record to be very specific one but vshard rebalancing came and added some dml record. Use pending_schema_change from pico property instead.
- Close: #554 (closed)
- Cherry-pick to: none
- Docs follow-up: not necessary