os: TestChmod failures with The parameter is incorrect. on Windows

[gopherbot]

#!watchflakes
post <- pkg == "os" && test == "TestChmod" && `The parameter is incorrect`

Issue created automatically to collect these failures.

Example (log):

--- FAIL: TestChmod (0.00s)
    os_test.go:1278: chmod C:\Users\gopher\AppData\Local\Temp\1\_Go_TestChmod2722485006 0666: chmod C:\Users\gopher\AppData\Local\Temp\1\_Go_TestChmod2722485006: The parameter is incorrect.

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
post <- pkg == "os" && test == "TestChmod"

2023-03-07 22:05 windows-amd64-race go@99914db5 os.TestChmod (log)

--- FAIL: TestChmod (0.00s)
    os_test.go:1278: chmod C:\Users\gopher\AppData\Local\Temp\1\_Go_TestChmod2722485006 0666: chmod C:\Users\gopher\AppData\Local\Temp\1\_Go_TestChmod2722485006: The parameter is incorrect.

— watchflakes

[bcmills]

(CC @golang/windows)

[bcmills]

This test was enabled on Windows in CL 250077 for #39606 (CC @iwdgo), and I marked it as safe to run in parallel in CL 458015.

It's not at all clear to me why it would fail nondeterministically, although it's curious that the one failure reported here is on the -race builder. 🤔

[alexbrainman]

I just looked at the internal/poll.FD.Fchmod code again, and it does not look right to me. For example, why do we only set du.FileAttributes and not du.CreationTime and other fields here?

go/src/internal/poll/fd_windows.go

Lines 1027 to 1030 in 618fb4a

	var du windows.FILE_BASIC_INFO
	du.FileAttributes = attrs
	l := uint32(unsafe.Sizeof(d))
	return windows.SetFileInformationByHandle(fd.Sysfd, windows.FileBasicInfo, uintptr(unsafe.Pointer(&du)), l)

Our code appears to set CreationTime (and all time related fields) to 0. This is wrong. No?

We should extend os.TestChmod to compare file times before and after os.Chmod call.

Alex.