Update arming_state_transition calls

Add new fRunPreArmChecks flag
Add fRunPreArmChecks flag

This is to allow unit tests to be written which do not perform pre-arm
checks
Fix broken arming unit test

Also, update arming_state_transition calls to add new fRunPreArmChecks
flag.
Merge pull request #1255 from PX4/ArmingUTFix

Fix state transition unit tests