Update ctb pu map for I slice The update in I slice is required for P/B slices in the same frame for accessing neighbor pus. Bug: 62851602 Bug: 63522067 Test: re-run PoC from b/62851602 Change-Id: Ie5e43f1cd5649b2745b6527654bc24d8c7d42932 (cherry picked from commit 43f126112a8f2000cd0744f2fc5d545ff1a9a70c)