[PATCH 1/2] BaseTools: fix ucs-2 lookup on python 3.9

["Cole" <crobinso@redhat.com>]

python3.9 changed/fixed codec.register behavior to always replace
hyphen with underscore for passed in codec names:

  https://bugs.python.org/issue37751

So the custom Ucs2Search needs to be adapted to handle 'ucs_2' in
addition to existing 'ucs-2' for back compat.

This fixes test failures on python3.9, example:

======================================================================
FAIL: testUtf16InUniFile (CheckUnicodeSourceFiles.Tests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/builddir/build/BUILD/edk2-edk2-stable202002/BaseTools/Source/Python/AutoGen/UniClassObject.py", line 375, in PreProcess
    FileIn = UniFileClassObject.OpenUniFile(LongFilePath(File.Path))
  File "/builddir/build/BUILD/edk2-edk2-stable202002/BaseTools/Source/Python/AutoGen/UniClassObject.py", line 303, in OpenUniFile
    UniFileClassObject.VerifyUcs2Data(FileIn, FileName, Encoding)
  File "/builddir/build/BUILD/edk2-edk2-stable202002/BaseTools/Source/Python/AutoGen/UniClassObject.py", line 312, in VerifyUcs2Data
    Ucs2Info = codecs.lookup('ucs-2')
LookupError: unknown encoding: ucs-2

Signed-off-by: Cole Robinson <crobinso@redhat.com>
---
 BaseTools/Source/Python/AutoGen/UniClassObject.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/BaseTools/Source/Python/AutoGen/UniClassObject.py b/BaseTools/Source/Python/AutoGen/UniClassObject.py
index b2895f7e5c..883c2356e0 100644
--- a/BaseTools/Source/Python/AutoGen/UniClassObject.py
+++ b/BaseTools/Source/Python/AutoGen/UniClassObject.py
@@ -152,7 +152,7 @@ class Ucs2Codec(codecs.Codec):
 
 TheUcs2Codec = Ucs2Codec()
 def Ucs2Search(name):
-    if name == 'ucs-2':
+    if name in ['ucs-2', 'ucs_2']:
         return codecs.CodecInfo(
             name=name,
             encode=TheUcs2Codec.encode,
-- 
2.26.2