os: TestProcessAlreadyDone failures

[gopherbot]

#!watchflakes
default <- pkg == "os" && test == "TestProcessAlreadyDone"

Issue created automatically to collect these failures.

Example (log):

=== RUN   TestProcessAlreadyDone
    exec_test.go:97: Wait() got err wait6: no child processes (ps <nil>), want ErrProcessDone
--- FAIL: TestProcessAlreadyDone (0.00s)

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
default <- pkg == "os" && test == "TestProcessAlreadyDone"

2024-06-10 22:06 gotip-freebsd-riscv64 go@beaf7f32 os.TestProcessAlreadyDone (log)

=== RUN   TestProcessAlreadyDone
    exec_test.go:97: Wait() got err wait6: no child processes (ps <nil>), want ErrProcessDone
--- FAIL: TestProcessAlreadyDone (0.00s)

— watchflakes