Fix rocksdb error when shutting down and processing at the same time.

[asdacap]

Fixes #4233

Fix exception on shutting down when TrieStore attempt to dispose batch while another thread is updating it.

Changes:

• Dont shotdown first on start. TrieStore already in dispose stack.

Types of changes

What types of changes does your code introduce?
Put an x in the boxes that apply

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Other (please describe):

Testing

Requires testing

• Yes
• No

In case you checked yes, did you write tests??

• Yes
• No

Comments about testing , should you have some (optional)

• Run ropsten with full sync only. Start and stop 10 consecutive time during sync, no more exception. Previously it would take less than 5 tries.

[LukaszRozmej]

Generally looks good, but please test some scenarios before merging, including different shutdown modes.

[asdacap]

What kind of shutdown modes?

[LukaszRozmej]

What kind of shutdown modes?

In-docker for example.

[asdacap]

SIGTERM/SIGINT works the same as expected. SIGKILL causes a lot of replay as expected, which another SIGTERM reduce.