Swap forseti clients over to using primitive maps.

Replace Forseti clients usage of regular hashmaps with hopscotch primitive
maps for tracking local lock counts. This makes a large section of the forseti
hot path GC free.

Also includes the optimization from RecordChanges where we allocate a new map
if the existing map has gotten larger than 32 entries.
Merge pull request #3408 from jakewins/2.1-forseti-gc

Swap forseti clients over to using primitive maps.