Refactored setting of completion policy to not overwrite JSR defaults
Prevent NPE when checking for a re-runnable continued flow, remove usage of
state transition comparator in FlowParser, ensure custom exit code is set at
job level.

Fixes TCK test testDeciderExitStatusIsSetOnJobContext, contributes but does
not fix decider transition tests that include restart.
Added new EndState to support JSR behavior for setting the JobExecution#exitStatus
Fixed merge issue from Job scope merge