- don't store pending tx signatures and costs in CostTracker
- apply tx costs to global state immediately again
- go from commit_or_cancel to update_or_remove, where the cost tracker
is either updated with the true costs for successful tx, or the costs
of a retryable tx is removed
- move the function into qos_service and hold the cost tracker lock for
the whole loop
(cherry picked from commit 924b8ea1eb)
864253a85b