Fix std.os.unlinkatW for absolute paths
Fix std.os.unlinkatW for absolute paths

RootDirectory can't be set in ObjectAttributes if ObjectName is an absolute path.

Fixes #4606

zig-lang/zig,raulgrell/zig,raulgrell/zig,raulgrell/zig,raulgrell/zig,andrewrk/zig,andrewrk/zig,zig-lang/zig,raulgrell/zig,zig-lang/zig