A number of JSON driven tests has a bug when they always fail in async tests.

For example(there are more of them): JsonDrivenAssertSessionPinnedTest: https://github.com/mongodb/mongo-csharp-driver/blob/master/tests/MongoDB.Driver.Tests/JsonDrivenTests/JsonDrivenAssertSessionPinnedTest.cs#L32

The only logic in the test is asserting, however since ActAsync is not overwritten, calling this test from the async mode will always trigger NotImplemented exception. The only reason why we don't see this exception because we overwrite the base implementation for Assert and as a result, we just ignore the thrown exception..