Use EnumTimeFormatsEx() to test panics across callback boundaries
instead of EnumWindows(). EnumWindows() is incompatible with Go's panic
unwinding mechanism. See the associated issue for more information.

Updates #26148

Change-Id: If1dd70885d9c418b980b6827942cb1fd16c73803
Reviewed-on: https://go-review.googlesource.com/c/155923
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>