Multiversion Tests

These tests test upgrade/downgrade behavior expected between different versions of MongoDB.

Those that begin failing upon branching should be assessed by the owner teams:

• Is the test only applicable to specific versions during specific development cycles? If so, delete it from irrelevant branches and master.
• Does the test add value for "last" (dynamic) version features? If so, modify the test to be more robust. These should always pass regardless of MongoDB version.