net/http: timeout in TestStreamingGet_h1 on ios-arm64-corellium

[bcmills]

2021-02-19T01:19:01-4da0188/ios-arm64-corellium

panic: test timed out after 3m0s

goroutine 160 [semacquire]:
internal/poll.runtime_Semacquire(0x1300a3028)
	/tmp/workdir-host-ios-arm64-corellium-ios/go/src/runtime/sema.go:61 +0x38
internal/poll.(*FD).Close(0x1300a3000, 0x1300a3000, 0x0)
	/tmp/workdir-host-ios-arm64-corellium-ios/go/src/internal/poll/fd_unix.go:115 +0x84
net.(*netFD).Close(0x1300a3000, 0x2, 0x0)
	/tmp/workdir-host-ios-arm64-corellium-ios/go/src/net/fd_posix.go:37 +0x48
net.(*conn).Close(0x13012a588, 0x0, 0x0)
	/tmp/workdir-host-ios-arm64-corellium-ios/go/src/net/net.go:207 +0x58
net/http.(*persistConn).closeLocked(0x130015b00, 0x104ad9798, 0x13011ace0)
	/tmp/workdir-host-ios-arm64-corellium-ios/go/src/net/http/transport.go:2704 +0x110
net/http.(*persistConn).close(0x130015b00, 0x104ad9798, 0x13011ace0)
	/tmp/workdir-host-ios-arm64-corellium-ios/go/src/net/http/transport.go:2689 +0x94
net/http.(*Transport).CloseIdleConnections(0x1300c08c0)
	/tmp/workdir-host-ios-arm64-corellium-ios/go/src/net/http/transport.go:768 +0x114
net/http_test.(*clientServerTest).close(0x13007ff80)
	/tmp/workdir-host-ios-arm64-corellium-ios/go/src/net/http/clientserver_test.go:45 +0x2c
net/http_test.testStreamingGet(0x13032cd80, 0x1045e7e00)
	/tmp/workdir-host-ios-arm64-corellium-ios/go/src/net/http/client_test.go:795 +0x4a4
net/http_test.TestStreamingGet_h1(0x13032cd80)
	/tmp/workdir-host-ios-arm64-corellium-ios/go/src/net/http/client_test.go:755 +0x2c
testing.tRunner(0x13032cd80, 0x104acd408)
	/tmp/workdir-host-ios-arm64-corellium-ios/go/src/testing/testing.go:1194 +0xe0
created by testing.(*T).Run
	/tmp/workdir-host-ios-arm64-corellium-ios/go/src/testing/testing.go:1239 +0x21c

…

FAIL	net/http	180.120s

It's not obvious to me whether TestStreamingGet_h1 was what actually consumed the time, or just happened to be running when the timeout occurred due to other tests taking too long.

CC @cherrymui @bradfitz @neild @empijei