OverlayPortal attaches its overlaychild's renderobject to overlay directly while keeps its semantics tree under overlayportal.
This become a problem when the `overlaychild` markNeedsSemanticsUpdate that it propagate upward the rendering tree.
This means instead of marking dirty upward to the OverlayPortal, it directly mark Overlay dirty instead and skip `OverlayPortal`.
Currently this does not pose an issue other than unnecessary rebuilds, but it become a problem when I try to optimize the semantics tree compilation https://github.com/flutter/flutter/pull/150394.
After the optimization it won't rebuild semantics node unless it is marked dirty. Since the OverlayPortal widget does not get marked dirty, it won't update the subtree.
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