Implement SubmittedJobGraphListener interface in Dispatcher

Call start() on SubmittedJobGraphStore with Dispatcher as listener. To enable
this, the dispatcher must implement the SubmittedJobGraphListener interface. Add
simple unit tests for the new methods. Refactor DispatcherTest to remove
redundancy.

[FLINK-8176][flip6] Make InMemorySubmittedJobGraphStore thread-safe

[FLINK-8176][flip6] Add method isStarted() to TestingLeaderElectionService

[FLINK-8176][flip6] Return same RunningJobsRegistry instance from TestingHighAvailabilityServices

[FLINK-8176][flip6] Fix race conditions in Dispatcher and DispatcherTest

Check if jobManagerRunner exists before submitting job.
Replace JobManagerRunner mock used in tests with real instance.
Do not run job graph recovery in actor main thread when job graph is recovered
from SubmittedJobGraphListener#onAddedJobGraph(JobID).

[FLINK-8176][flip6] Rename variables in DispatcherTest

[FLINK-8176][flip6] Remove injectMocks in DispatcherTest

[FLINK-8176][flip6] Update Dispatcher's SubmittedJobGraphListener callbacks

Always attempt the job submission if onAddedJobGraph or onRemovedJobGraph are
called. The checks in submitJob and removeJob are sufficient.

This closes #5107.

This closes #5129.

This closes #5157.

This closes #5153.

This closes #8213.

This closes #5099.

This closes #5127.

Previously, the ResultPartitionWriter implemented the EventListener interface
and was used for event registration, although event publishing was already
handled via the TaskEventDispatcher. Now, we use the TaskEventDispatcher for
both, event registration and publishing.

It also adds the TaskEventDispatcher to the Environment information for a task
to be able to work with it (only IterationHeadTask so far).

This closes #4761.

This closes #5147.

This closes #5146.

This closes #5115.

This closes #5064.

This closes #5152.

This closes #5052.

[FLINK-8174] Mesos RM unable to accept offers for unreserved resources
- added test `OfferTest`

[FLINK-8174] Mesos RM unable to accept offers for unreserved resources
- fix `LaunchCoordinatorTest`

[FLINK-8174] Mesos RM unable to accept offers for unreserved resources
- improved javadocs

[FLINK-8174] Mesos RM unable to accept offers for unreserved resources
- rename `print` to `toString`
- precalculate offer resource values
- extend TestLogger

This closes #5114.

This closes #5118.

The TaskManagerServicesTest was extremely slow because it uses the PowerMockRunner
for a single test case. Additionally some other tests test different settings in
a loop which was quite slow because the PowerMockRunner instrumented all method calls.
Moving the test which required the PowerMockRunner into a separate test class sped up
things by a factor of 50.

Before, AvroUtils were loaded when the class was loaded which didn't
take into account the user-code ClassLoader. Now, we try loading avro
utils with the Thread context ClassLoader.

Replace wait on lock with OneShotLatch to resolve race condition between task
start up and unblocking of invokable.

This closes #5117.

This closes #4504.