[Win][Clang] Remove -fmsc-version=1911 compiler switch 190776@main (bug#173889) added -fmsc-version=1911 compiler switch for clang-cl. However, it seems that it is no longer needed.
Pull request: https://github.com/WebKit/WebKit/pull/19187
Committed 269438@main (a89b68fd1a99): <https://commits.webkit.org/269438@main> Reviewed commits have been landed. Closing PR #19187 and removing active labels.