net: timeout in TestDNSSRVUniformity on linux-mips64le-rtrk

[bcmills]

panic: test timed out after 12m0s

goroutine 105 [running]:
testing.(*M).startAlarm.func1()
	/tmp/gobuilder-mips64le/go/src/testing/testing.go:1743 +0x104
created by time.goFunc
	/tmp/gobuilder-mips64le/go/src/time/sleep.go:180 +0x5c

goroutine 1 [chan receive]:
testing.(*T).Run(0xc00019c180, 0x1202e111a, 0x14, 0x1202eedc0, 0x120116e01)
	/tmp/gobuilder-mips64le/go/src/testing/testing.go:1282 +0x2fc
testing.runTests.func1(0xc000082780)
	/tmp/gobuilder-mips64le/go/src/testing/testing.go:1554 +0x8c
testing.tRunner(0xc000082780, 0xc0000d9d90)
	/tmp/gobuilder-mips64le/go/src/testing/testing.go:1236 +0xf8
testing.runTests(0xc0000b8030, 0x120468680, 0xef, 0xef, 0xc00c1c584b6ffa75, 0xa7a3b36ca3, 0x120487100, 0x10)
	/tmp/gobuilder-mips64le/go/src/testing/testing.go:1552 +0x338
testing.(*M).Run(0xc0000de000, 0x0)
	/tmp/gobuilder-mips64le/go/src/testing/testing.go:1460 +0x1e0
net.TestMain(0xc0000de000)
	/tmp/gobuilder-mips64le/go/src/net/main_test.go:53 +0x4c
main.main()
	_testmain.go:593 +0x198

goroutine 117 [runnable]:
net.byPriorityWeight.shuffleByWeight(0xc0001d4000, 0x3, 0x3)
	/tmp/gobuilder-mips64le/go/src/net/dnsclient.go:172 +0x1c
net.checkDistribution(0xc00019c180, 0xc00019e090, 0x3, 0x3, 0x3fb999999999999a)
	/tmp/gobuilder-mips64le/go/src/net/dnsclient_test.go:23 +0x1ac
net.testUniformity(0xc00019c180, 0x3, 0x3fb999999999999a)
	/tmp/gobuilder-mips64le/go/src/net/dnsclient_test.go:45 +0x170
net.TestDNSSRVUniformity(0xc00019c180)
	/tmp/gobuilder-mips64le/go/src/net/dnsclient_test.go:50 +0x7c
testing.tRunner(0xc00019c180, 0x1202eedc0)
	/tmp/gobuilder-mips64le/go/src/testing/testing.go:1236 +0xf8
created by testing.(*T).Run
	/tmp/gobuilder-mips64le/go/src/testing/testing.go:1281 +0x2dc
FAIL	net	720.061s

2021-03-15T21:49:19-de2b27d/linux-mips64le-rtrk

Not clear to me whether this is a defect in the test itself, the code under test, or the platform / builder.

CC @bogojevic @milanknezevic