Junos: add some ipsec crash protection

[dhalperi]

No description provided.

[batfish-bot]

This change is 

[codecov]

Codecov Report

Attention: Patch coverage is 90.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 72.70%. Comparing base (12d3018) to head (85d0ea1).
Report is 73 commits behind head on master.

Files with missing lines	Patch %	Lines
...h/representation/juniper/JuniperConfiguration.java	90.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #9152   +/-   ##
=======================================
  Coverage   72.69%   72.70%           
=======================================
  Files        3314     3314           
  Lines      169832   169843   +11     
  Branches    19995    19999    +4     
=======================================
+ Hits       123467   123477   +10     
- Misses      37202    37205    +3     
+ Partials     9163     9161    -2     

Files with missing lines	Coverage Δ
...h/representation/juniper/JuniperConfiguration.java	86.09% <90.00%> (+0.34%)	⬆️

... and 2 files with indirect coverage changes

[progwriter]

Reviewed 3 of 3 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @anothermattbrown)