kvserver: add e2e rac2 send queue functionality tests

[kvoli]

For https://github.com/cockroachdb/cockroach/issues/128040 we modified the existing TestFlowControl.*V2 e2e integration tests to also have a pull-mode (send queue) variation.

This issue is to add new tests which purposefully exhaust send tokens and assert on the send queue formation, force flushing and token deduction to prevent send queue formation.

Jira issue: CRDB-43177

Epic CRDB-42900

[kvoli]

Removing the GA blocker, I will still backport these tests to v24.3 using a testing change justification.

These pertain to disabled by default behavior in v24.3, hence the removal.

[kvoli]

https://github.com/cockroachdb/cockroach/pull/133757 adds a general test. We should also add tests which force interesting events, similar to the existing TestFlowControl.*V2 tests, but while send tokens are exhausted on one or more streams.

A non-exhaustive (or binding) list of variations to add, in approximate order by usefulness:

• TestFlowControlSendQueueRangeSplitMerge
• TestFlowControlSendQueueTransferLease
• TestFlowControlSendQueueRaftMembershipRemoveSelf
• TestFlowControlSendQueueRaftMembership
• TestFlowControlSendQueueRaftSnapshot
• TestFlowControlSendQueueLeaderNotLeaseholder
• TestFlowControlSendQueueGranterAdmitOneByOne

See the existing V2 integration test variants, which were used to construct this list:

https://github.com/cockroachdb/cockroach/blob/ef26d1534507f6089aa909e0bd43a0efb71dd6c7/pkg/kv/kvserver/flow_control_integration_test.go#L2303-L2305