kvcoord: evict range cache on unsplittable batches

[erikgrinaker]

Prototype fix for #119333. Possibly not ideal or backportable, since we can end up evicting range descriptors too often, incurring meta lookup latency.

Maybe we can eagerly refresh the cache here and pay the cost only for the unsplittable requests instead, which are less latency-sensitive (AddSSTable and Barrier).

Epic: none
Release note: None

[blathers-crl]

It looks like your PR touches production code but doesn't add or edit any test code. Did you consider adding tests to your PR?

_{🦉 Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf.}

[cockroach-teamcity]

This change is 

[erikgrinaker]

Kicking off 10 runs of c2c/tpcc/warehouses=1000/duration=60/cutover=30 to verify.

[erikgrinaker]

Kicking off 10 runs of c2c/tpcc/warehouses=1000/duration=60/cutover=30 to verify.

10/10 passed.

[erikgrinaker]

Closing in favor of #119512.