net/http: TestOmitHTTP2 failures

[gopherbot]

#!watchflakes
post <- pkg == "net/http" && test == "TestOmitHTTP2" && `Expected proxy copy error`

Issue created automatically to collect these failures.

Example (log):

--- FAIL: TestOmitHTTP2 (6.85s)
    http_test.go:93: go test -short failed: exit status 1, --- FAIL: TestTransportAndServerSharedBodyReqCancelerCleanupOnConnectionClose (0.00s)
            --- FAIL: TestTransportAndServerSharedBodyReqCancelerCleanupOnConnectionClose/h1 (0.51s)
                transport_test.go:6824: Backend address: 127.0.0.1:34785
                transport_test.go:6842: Proxy address: 127.0.0.1:42763
                transport_test.go:6838: Expected proxy copy error
        FAIL
        FAIL	net/http	2.226s
        FAIL

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
default <- pkg == "net/http" && test == "TestOmitHTTP2"

2023-08-23 05:58 linux-amd64-longtest-race go@e68c0272 net/http.TestOmitHTTP2 (log)

--- FAIL: TestOmitHTTP2 (6.85s)
    http_test.go:93: go test -short failed: exit status 1, --- FAIL: TestTransportAndServerSharedBodyReqCancelerCleanupOnConnectionClose (0.00s)
            --- FAIL: TestTransportAndServerSharedBodyReqCancelerCleanupOnConnectionClose/h1 (0.51s)
                transport_test.go:6824: Backend address: 127.0.0.1:34785
                transport_test.go:6842: Proxy address: 127.0.0.1:42763
                transport_test.go:6838: Expected proxy copy error
        FAIL
        FAIL	net/http	2.226s
        FAIL

— watchflakes

[bcmills]

Duplicate of #62224

[bcmills]

I've updated the watchflakes pattern for that issue, and will remove this one from the Test Flakes project.