logictest: use a retry loop when starting testserver

[rafiss]

A similar change was already made for upgrading the node.

informs #94956

Release note: None

[cockroach-teamcity]

This change is 

[renatolabs]

LGTM.

Do you have the context for the backwards compatibility we are trying to achieve here?

https://github.com/cockroachdb/cockroach-go/blob/d51b7cdc21ea0529ca81ed61c313e44763d0ac3e/testserver/testserver.go#L422-L425

It would be nice if the absence of custom ports meant the testserver bound to :0 (i.e., let the kernel choose). It would eliminate the flakes we're seeing and we wouldn't need to perform any retries from logictest.

[rafiss]

Here's where that change was made: cockroachdb/cockroach-go#145

I believe the thinking was that any users of the library before that PR might have been writing tests that relied on the port to be fixed.

The hardcoding of ports was first added here: cockroachdb/cockroach-go#141. The reason it was added was because when stopping/restarting a node during the upgrade, you need to make sure it is listening on the same port as it was before. Otherwise other nodes won't be able to join it in the cluster.

However, I bet we can do better, maybe by referring back to the port that was in the listen-url file. I'll try to improve this in cockroach-go, but will merge this for now.

bors r=renatolabs

[craig]

Build failed:

• Bazel Essential CI (Cockroach)

[rafiss]

bors r+

[craig]

Build failed (retrying...):

• Bazel Essential CI (Cockroach)

[craig]

Build succeeded:

• Bazel Essential CI (Cockroach)