Test fast/text/flag-codepoint.html fails on WebKitGTK+ since it was added on r222576 <https://trac.webkit.org/r222576>. The failure is the following: https://build.webkit.org/results/GTK%20Linux%2064-bit%20Release%20(Tests)/r222577%20%283369%29/fast/text/flag-codepoint-diffs.html
passing since r239437. Updating expectations and closing bug.
<rdar://problem/47176579>