Fix gitattributes mismatches

This is due to the facts that:

1. this repository ships .gitattributes files
2. the CI pipeline forces on all files the attributes -text -eol -crlf -ident -filter -working-tree-encoding -export-subst
3. the package was likely originally imported in the repository without the above override, so the utf8_win.txt file was committed in its "normalized" form with LF line terminators instead of the CRLF that are actually expected

Fix the situation by:

1. setting the gitattributes override locally
2. extracting the orig tarball over the current sources
3. commit the changed files in their "denormalized" form, with CRLF line endings

Task: T6873