[release-branch.go1.18] testing: include ERROR_SHARING_VIOLATION in Windows cleanup retries

Fixes #52986
Updates #51442
Updates #50051

Change-Id: I1bfbc08c907077467fd50febbec6299a9b73af41
Reviewed-on: https://go-review.googlesource.com/c/go/+/388916
Trust: Bryan Mills <[email protected]>
Run-TryBot: Bryan Mills <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
(cherry picked from commit eeb9f09)
Reviewed-on: https://go-review.googlesource.com/c/go/+/407877
Reviewed-by: Nooras Saba‎ <[email protected]>
Auto-Submit: Bryan Mills <[email protected]>

Author: Bryan C. Mills

src/testing/testing.go

@@ -1122,7 +1122,7 @@ func removeAll(path string) error {
 	)
 	for {
 		err := os.RemoveAll(path)
-		if !isWindowsAccessDenied(err) {
+		if !isWindowsRetryable(err) {
 			return err
 		}
 		if start.IsZero() {

src/testing/testing_other.go

@@ -6,8 +6,8 @@
 
 package testing
 
-// isWindowsAccessDenied reports whether err is ERROR_ACCESS_DENIED,
-// which is defined only on Windows.
-func isWindowsAccessDenied(err error) bool {
+// isWindowsRetryable reports whether err is a Windows error code
+// that may be fixed by retrying a failed filesystem operation.
+func isWindowsRetryable(err error) bool {
 	return false
 }

src/testing/testing_windows.go

@@ -8,11 +8,25 @@ package testing
 
 import (
 	"errors"
+	"internal/syscall/windows"
 	"syscall"
 )
 
-// isWindowsAccessDenied reports whether err is ERROR_ACCESS_DENIED,
-// which is defined only on Windows.
-func isWindowsAccessDenied(err error) bool {
-	return errors.Is(err, syscall.ERROR_ACCESS_DENIED)
+// isWindowsRetryable reports whether err is a Windows error code
+// that may be fixed by retrying a failed filesystem operation.
+func isWindowsRetryable(err error) bool {
+	for {
+		unwrapped := errors.Unwrap(err)
+		if unwrapped == nil {
+			break
+		}
+		err = unwrapped
+	}
+	if err == syscall.ERROR_ACCESS_DENIED {
+		return true // Observed in https://go.dev/issue/50051.
+	}
+	if err == windows.ERROR_SHARING_VIOLATION {
+		return true // Observed in https://go.dev/issue/51442.
+	}
+	return false
 }