Arista: improve route-map parsing on older EOS

[dhalperi]

As reported by @dannypetrov, EOS 4.20.7 does not include action/line number
in output (in at least some cases). The new tests are based on behavior during
that discussion.

[batfish-bot]

This change is 

[progwriter]

Reviewed 5 of 5 files at r1.
Reviewable status: complete! all files reviewed, all discussions resolved

[codecov]

Codecov Report

Merging #6384 into master will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master    #6384      +/-   ##
============================================
- Coverage     73.06%   73.06%   -0.01%     
+ Complexity    35194    35189       -5     
============================================
  Files          2815     2815              
  Lines        142697   142700       +3     
  Branches      17170    17172       +2     
============================================
+ Hits         104261   104263       +2     
+ Misses        30192    30184       -8     
- Partials       8244     8253       +9     

Impacted Files	Coverage Δ	Complexity Δ
...sh/grammar/arista/AristaControlPlaneExtractor.java	34.09% <100.00%> (+0.27%)	602.00 <0.00> (+5.00)
.../batfish/representation/arista/RouteMapClause.java	70.83% <100.00%> (+2.65%)	8.00 <2.00> (+1.00)
...src/main/java/org/batfish/coordinator/PoolMgr.java	54.76% <0.00%> (-5.96%)	13.00% <0.00%> (-3.00%)
.../org/batfish/dataplane/rib/RouteAdvertisement.java	83.67% <0.00%> (-4.09%)	18.00% <0.00%> (-1.00%)
...src/main/java/org/batfish/coordinator/WorkMgr.java	75.44% <0.00%> (-0.62%)	244.00% <0.00%> (-3.00%)
...ain/java/org/batfish/coordinator/WorkQueueMgr.java	70.93% <0.00%> (-0.59%)	90.00% <0.00%> (-1.00%)
...java/org/batfish/dataplane/ibdp/VirtualRouter.java	90.54% <0.00%> (-0.34%)	208.00% <0.00%> (-1.00%)
...a/org/batfish/representation/aws/LoadBalancer.java	82.18% <0.00%> (-0.32%)	70.00% <0.00%> (-1.00%)
...tfish/representation/cisco/CiscoConfiguration.java	85.90% <0.00%> (-0.14%)	492.00% <0.00%> (-1.00%)
... and 2 more