net: TestFileListener/tcp failures

[gopherbot]

#!watchflakes
default <- pkg == "net" && test == "TestFileListener/tcp"

Issue created automatically to collect these failures.

Example (log):

=== RUN   TestFileListener/tcp
    file_test.go:184: file file+net tcp4:127.0.0.1:49927->: protocol not supported
--- FAIL: TestFileListener/tcp (0.00s)

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
default <- pkg == "net" && test == "TestFileListener/tcp"

2025-11-10 20:21 gotip-windows-amd64-longtest go@bf58e784 net.TestFileListener/tcp (log)

=== RUN   TestFileListener/tcp
    file_test.go:184: file file+net tcp4:127.0.0.1:49927->: protocol not supported
--- FAIL: TestFileListener/tcp (0.00s)

— watchflakes

[gopherbot]

Change https://go.dev/cl/734820 mentions this issue: net: don't ignore getsockname errors in newFileFD