roachtest: quiescence with dead node

[tbg]

This test currently fails, at least in remote mode (curiously in local
mode it works, at least on my laptop).

--- FAIL: kv/quiescence/nodes=3 [unstable] (1258.49s)
        kv.go:160: QPS dropped by more than 80%: from 2669.32 to 1582.14

Fixing this test is the goal for #9446.

Release note: None

[cockroach-teamcity]

This change is 

[petermattis]

I like that we're adding roachtests for scenarios like this.

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Review status: 0 of 2 files reviewed at latest revision, all discussions resolved, some commit checks failed.

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pkg/cmd/roachtest/kv.go, line 145 at r1 (raw file):

			const kv = "./workload run kv --duration=10m --read-percent=0"

			run("./workload run kv --init --max-ops=1 --splits 10000 --concurrency 100 {pgurl:1}", false)

I'm guessing 10k splits is necessary to highlight the lack of quiescence. Should indicate that in a comment.

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Comments from Reviewable

[tbg]

Updated. TFTR!

bors r=petermattis

[craig]

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