Bug 1742885 - Use valid Windows SDK dir in `--enable-path-remapping`, and...

Bug 1742885 - Use valid Windows SDK dir in `--enable-path-remapping`, and normalize SDK dirs. r=firefox-build-system-reviewers,glandium

Without normalization, the Windows SDK dirs are usually like
`c:/Program Files (x86)/Windows Kits/{8.1,10}`, which fails because
the build system (really, `cc-rs`) doesn't handle spaces in paths.

Differential Revision: https://phabricator.services.mozilla.com/D132287