test(Java): Cover more of LRU behavior

All CMCs are Least Recently Used cache.

This revises the test to ensure a very well used entry is never pruned.
The ALWAYS_PICKED entry is inserted right after cache construction with a very long time to live.

10 threads are spun up to test the CMC; 300_000 test over the threads are made to retrieve one of the 22 identifiers.

Each test randomly selects one of the 21 identifiers for a get.
If the get fails, the test issues a put.
The test also, always, issues a get for ID 22.

Cache Hits and Misses are tracked per ID.

Once all tests are completed, the hit/miss of the IDs is printed and some assertions are made, including that ID 22 was never evicted.