[cs] miscompilation of break in switch in do-while loop

[fourst4r]

This code doesn't compile on C# target.
Haxe 4.3.3

function main() {
    var o:haxe.ds.Option<Int> = None;
    do {
        switch(o) {
            case Some(_):
            case None: break;
        }
    }
    while( false );
}

src\_Main\Main_Fields_.cs(32,18): error CS1002: ; expected

The fix might be related to #6267