Fixed parsing the output of vswhere

[rainman110]

Changelog: Bugfix: Fixed the detection of certain visual c++ installations.
Docs: Omit

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The output of vswhere uses "Ansi" encoding. It was though decoded via "Utf-8", which raised an exception in certain cases (i.e. letters like 'ö').

This PR forces the output of vswhere to be utf-8, resolving the issue.

Thus, some visual studio installation could not be found.

Fixes #13281

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[rainman110]

@memsharded please have a look to this. This fixes the Visual Studio detection.

[rainman110]

@memsharded An alternative to this PR would be to force utf-8 encoding by adding the "-utf-8" argument to vswhere, see:
https://github.com/microsoft/vswhere/wiki/Encoding

[rainman110]

@memsharded I now follow the other approach by forcing utf-8. Works nicely locally.

[memsharded]

@memsharded I now follow the other approach by forcing utf-8. Works nicely locally.

Excellent, I think it seems a little less risky than the alternative, lets see how it goes.
Thanks very much for contributing it!