Fix 3917 jump vehicles with motive damage

[Sleet01]

This adds the ability for CVs that are "immobilized" by Motive System hits to jump.

Per linked issue, CVs with jump jets should be able to jump even when motive system damage has reduced MP to 0.
When an "immobilized" CV with jump jets jumps, it does not get the -4 TMM for being immobile.
Additionally, when the crew is Stunned, they can still move up to Cruise MP, which means they can still jump.

States that now prevent JJ-equipped CVs from jumping:

• Vehicle destroyed (ob.)
• Engine destroyed
• Crew killed
• Crew ejected
• Crew unconscious (not sure if this is possible for CVs but included in existing checks)
• Engine shut down (again, not sure if possible but included per some other checks)

Added a unit test to EntityTest.java to verify correct handling of these states.

Close #3917