net: TestLookupGoogleSRV failures about go

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
default <- pkg == "net" && test == "TestLookupGoogleSRV"

2024-03-27 19:24 linux-loong64-3a5000 go@efb7cc42 net.TestLookupGoogleSRV (log)

2024/03/28 03:35:27 killing splice client after 5 second shutdown timeout
panic: test timed out after 3m0s
running tests:
	TestCloseRead (10s)
	TestCloseWrite (10s)
	TestConnClose (10s)
	TestListenerClose (10s)
	TestLookupGmailMX (10s)
	TestLookupGmailNS (10s)
	TestLookupGmailTXT (10s)
...
	/tmp/workdir-host-linux-loong64-3a5000/go/src/net/lookup.go:713 +0x20c fp=0xc000403ca8 sp=0xc000403098 pc=0x120192b1c
net.(*Resolver).lookupSRV(...)
	/tmp/workdir-host-linux-loong64-3a5000/go/src/net/lookup_unix.go:104
net.(*Resolver).LookupSRV(0x12049cae0, {0x120333ea0, 0x1204cbbc0}, {0x1202d3deb, 0x4}, {0x1202d3c1a, 0x3}, {0x1202d5aef, 0xa})
	/tmp/workdir-host-linux-loong64-3a5000/go/src/net/lookup.go:515 +0x78 fp=0xc000403d80 sp=0xc000403ca8 pc=0x120191aa8
net.LookupSRV({0x1202d3deb, 0x4}, {0x1202d3c1a, 0x3}, {0x1202d5aef, 0xa})
	/tmp/workdir-host-linux-loong64-3a5000/go/src/net/lookup.go:497 +0x80 fp=0xc000403e08 sp=0xc000403d80 pc=0x1201919e0
net.TestLookupGoogleSRV(0xc000332b60)
	/tmp/workdir-host-linux-loong64-3a5000/go/src/net/lookup_test.go:89 +0x194 fp=0xc000403f68 sp=0xc000403e08 pc=0x1201f5014
testing.tRunner(0xc000332b60, 0x1202ec3f0)

— watchflakes