utils: Use _wfopen and _wreopen on Windows

Summary:
The fopen function does not support unicode filename on Windows, so use Windows specific function do deal with it

This is a backport of Core PR13866

Test Plan:
ninja && ninja check

Use the build bot to run tests on windows.

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D8343