- Use corresponding entry in the manifest, as described in
https://docs.microsoft.com/en-us/windows/apps/design/globalizing/use-utf8-code-page

- If if ANSI codepage is UTF8 (i.e for Windows 1903 and later)
  Use UTF8 as default client charset
  Set console codepage(s) to UTF8, in case process is using console

- Allow some previously disabled MTR tests, that used Unicode for in "exec",
  for the recent Windows versions