Ignore some new PNG files in ci_built_diff.sh (web-platform-tests#11561)

PR web-platform-tests#11362 introduced some new PNG files similar to their counterparts in
2dcontext (also font-rendering specific), so we need to ignore these
files in tools/ci/ci_built_diff.sh, too.

Author: Hexcles

tools/ci/ci_built_diff.sh

@@ -15,6 +15,10 @@ main() {
         '2dcontext/drawing-text-to-the-canvas/2d.text.draw.fill.maxWidth.large.png'
         '2dcontext/drawing-text-to-the-canvas/2d.text.draw.fill.rtl.png'
         '2dcontext/drawing-text-to-the-canvas/2d.text.draw.stroke.basic.png'
+        'offscreen-canvas/text/2d.text.draw.fill.basic.png'
+        'offscreen-canvas/text/2d.text.draw.fill.maxWidth.large.png'
+        'offscreen-canvas/text/2d.text.draw.fill.rtl.png'
+        'offscreen-canvas/text/2d.text.draw.stroke.basic.png'
     )
 
     ./update-built-tests.sh