Intern OSPF routes

[progwriter]

Helps reduce memory pressure in certain scenarios.

[batfish-bot]

This change is 

[codecov]

Codecov Report

Merging #3728 into master will decrease coverage by <.01%.
The diff coverage is 100%.

@@             Coverage Diff              @@
##             master    #3728      +/-   ##
============================================
- Coverage     73.59%   73.58%   -0.01%     
- Complexity    24010    24012       +2     
============================================
  Files          2045     2045              
  Lines         98628    98632       +4     
  Branches      11902    11902              
============================================
+ Hits          72581    72583       +2     
- Misses        20702    20704       +2     
  Partials       5345     5345

Impacted Files	Coverage Δ	Complexity Δ
...java/org/batfish/datamodel/OspfIntraAreaRoute.java	82.6% <100%> (+3.06%)	17 <1> (+2)	⬆️
.../java/org/batfish/datamodel/OspfExternalRoute.java	84.21% <100%> (+1.54%)	19 <1> (+2)	⬆️
...java/org/batfish/datamodel/OspfInterAreaRoute.java	80.76% <100%> (+2.33%)	17 <1> (+2)	⬆️
...g/batfish/datamodel/acl/IpAccessListLineIndex.java	33.33% <0%> (-5.56%)	4% <0%> (-1%)
...col/src/main/java/org/batfish/role/InferRoles.java	91.01% <0%> (-1.18%)	69% <0%> (-1%)
...src/main/java/org/batfish/coordinator/PoolMgr.java	64.04% <0%> (-1.13%)	15% <0%> (-1%)

[dhalperi]

Reviewed 3 of 3 files at r1.
Reviewable status: complete! all files reviewed, all discussions resolved