BaseTools/UPT:merge UPT Tool use Python2 and Python3

In UPT Tool,merge python2 and python3

Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Zhiju.Fan <zhijux.fan@intel.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>

BaseTools/Source/Python/UPT/Library/ParserValidate.py

@@ -727,7 +727,7 @@ def IsValidUserId(UserId):
 #
 def CheckUTF16FileHeader(File):
     FileIn = open(File, 'rb').read(2)
-    if FileIn != '\xff\xfe':
+    if FileIn != b'\xff\xfe':
         return False
 
     return True