2022-April-23 - Prerelease - 2.6.700

Optimize getNeighbors(). (#10357)

Two small tweaks to getNeighbors() result in a 2x speed up in my testing of logic related to calculations when moving air units:
  - Use a regular stream, not parallel, since the direct neighbors of a given territory will be usually less than 10 (and never really in thousands+).
  - No need for getOrDefault() since `connections` is always populated.