Run more tests concurrently in CI

[jyemin]

Make these suites run concurrently on the main matrices

• driver-sync
• driver-reactive-streams
• driver-core
• driver-legacy

Additionally, run unit tests once per JDK rather than on every MongoDB deployment variant

• bson
• mongodb-crypt

JAVA-5628

Patch builds show that the slowest task drops from ~45 minutes to ~20 minutes

[rozza]

I like it. One comment about the legacy tests but it looks good 👍

[rozza]

So kotlin tests are duplicated here but the Scala driver tests aren't.

As we already limit the versions that we run kotlin / scala on and Scala tests multiple scala runtimes. I'd recommend removing them from the bson and reactive tests.

[jyemin]

I have an optional suggestion - put the "test" prefix after.

It reads better with test as a suffix, but I prefer the prefix because then they all sort together

[jyemin]

Added @katcharov to get one more set of eyes on this.