Scope

Investigate solutions and consider adding driver integration tests in libmongocrypt to catch regressions on master.

Background & Motivation

Some libmongocrypt changes inadvertently break driver tests, and are only caught by drivers that test with the master branch. This causes churn on those changes.

Examples:

• MONGOCRYPT-306 changed an error message. This failed driver tests and required a follow-up change https://github.com/mongodb/libmongocrypt/pull/437
• MONGOCRYPT-457 exposed a bug in drivers-evergreen-tools scripts. This failed driver tests and required a follow-up change: https://github.com/mongodb-labs/drivers-evergreen-tools/pull/220