As of SERVER-33548, when profiling is enabled, we expect profile writes for operations inside of transactions to appear in system.profile independently of whether the transaction commits. This transactions override test asserts that the operations are not visible in system.profile, and seems to have been passing because of visibility rules for reads inside transactions (see my comment).

As of SERVER-46900, it's not possible to read from system.profile inside of a transaction. Upon modifying the transactions override framework to not run the read to system.profile inside of a transaction, the jstests/libs/txns/txn_passthrough_runner_selftest.js fails because this read returns nonempty results, as expected.

SERVER-46900 will blacklist the offending find and any other dependent portions in the test.