storage: Fix hang on shutdown for multi-node tests
storage: Fix hang on shutdown for multi-node tests

When a multi-node cluster shuts down and a majority completes their
shutdown before the minority manages to drain, requests could get
stuck on `addWriteCmd` (since no quorum is available). There's a
RunTask in the call stack, so that this would prevent shutdown.

Now we abandon commands as soon as we try to quiesce.

Fixes #9429.
Fixes #8890.
Fixes #9269.
Fixes #9285.

cockroachdb/cockroach,paperstreet/cockroach,glycerine/cockroach,veteranlu/cockroach,cockroachdb/cockroach,glycerine/cockroach,maxlang/cockroach,petermattis/cockroach,maxlang/cockroach,glycerine/cockroach,vaibhavarora/cockroach,petermattis/cockroach,petermattis/cockroach,veteranlu/cockroach,petermattis/cockroach,glycerine/cockroach,maxlang/cockroach,petermattis/cockroach,glycerine/cockroach,paperstreet/cockroach,glycerine/cockroach,paperstreet/cockroach,veteranlu/cockroach,cockroachdb/cockroach,veteranlu/cockroach,vaibhavarora/cockroach,paperstreet/cockroach,veteranlu/cockroach,veteranlu/cockroach,cockroachdb/cockroach,maxlang/cockroach,paperstreet/cockroach,vaibhavarora/cockroach,veteranlu/cockroach,cockroachdb/cockroach,maxlang/cockroach,vaibhavarora/cockroach,cockroachdb/cockroach,petermattis/cockroach,paperstreet/cockroach,cockroachdb/cockroach,cockroachdb/cockroach,petermattis/cockroach,maxlang/cockroach,paperstreet/cockroach,glycerine/cockroach,paperstreet/cockroach,vaibhavarora/cockroach,veteranlu/cockroach,vaibhavarora/cockroach,maxlang/cockroach,petermattis/cockroach,vaibhavarora/cockroach,maxlang/cockroach,vaibhavarora/cockroach,glycerine/cockroach