REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1080
Per Shell spec 2.2 chapter 3.4.4.2, Unicode file tag should be
inserted in the output from the input redirected variable, to ensure
it looks like a UCS-2 encode file.
The patch fixes this issue.
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>