Enable buggify for Report Conflict Keys and ConflictRange Tests

The PR https://github.com/apple/foundationdb/pull/2860#pullrequestreview-384323215 introduces a new test workload for ReportConflictKeys feature. The workload mimics the existing ConflictRange test and disabled the buggify.

The reason why buggify is disabled is clear. It also simplify the test. However, it means we leave some code untested.

It is better to be able to toggle buggify for both tests. It at lease help us know if the new feature have negative impact on the existing features under buggify=on.

If buggify causes a transaction to fail on other errors, the test can retry.