net/http: TestServerConnState is flaky on darwin-arm64-corellium builder

[bcmills]

Issue #32329 was addressed in December. Since that time, TestServerConnState has continued to flake, but only on the darwin-arm64-corellium builder.

I'm not sure whether this is a bug in the builder, or a general bug that this builder just happens to trigger (for example, due to unusual performance characteristics).

2020-02-19T22:04:41-3457359/darwin-arm64-corellium
2020-02-07T16:49:14-1a37095/darwin-arm64-corellium
2020-01-31T05:52:03-862a57d/darwin-arm64-corellium
2020-01-29T14:58:15-1319bb9/darwin-arm64-corellium

--- FAIL: TestServerConnState (5.06s)
    serve_test.go:4227: Timed out waiting for connection to change state.
    serve_test.go:4227: Request(s) produced unexpected state sequence.
        Got:  [new]
        Want: [new closed]
    serve_test.go:4172: unexpected conn in state closed
FAIL
FAIL	net/http	10.571s

[bcmills]

Is it possible that this builder is just so slow that a 5-second timeout is insufficient? Perhaps we should raise the timeout and see if it persists.

[bcmills]

2020-03-06T23:33:17-b00ebea/darwin-arm64-corellium
2020-02-19T22:04:41-3457359/darwin-arm64-corellium
2020-02-07T16:49:14-1a37095/darwin-arm64-corellium
2020-01-31T05:52:03-862a57d/darwin-arm64-corellium

[gopherbot]

Change https://golang.org/cl/222957 mentions this issue: net/http: use t.Deadline instead of an arbitrary timeout in TestServerConnState

[bcmills]

CC @znly

[bcmills]

No recent failures on any kind of darwin:

greplogs --dashboard -md -l -e 'FAIL: TestServerConnState' --since=2021-01-01

2022-01-19T20:54:49-1efc581/plan9-arm
2021-11-17T19:50:58-88474d4/openbsd-386-68