Remove all remaining readers and writers for TABLE_COMMIT
Summary: Depends on D20459. Ref T13276. I'll file a followup to actually destroy the table.
Test Plan:
- Grepped for TABLE_COMMIT.
- Ran bin/storage upgrade -f, got a clean bill of health.
Reviewers: amckinley
Reviewed By: amckinley
Maniphest Tasks: T13276
Differential Revision: https://secure.phabricator.com/D20461