Add a failing text test

testsuite/gsk/compare/o-from-hell.node

@@ -0,0 +1,16 @@
+blend {
+  mode: difference;
+  bottom: text {
+    color: rgb(255,0,0);
+    font: "Noto Sans Mono 300";
+    glyphs: "o";
+  }
+  top: transform {
+    transform: scale(100);
+    child: text {
+      color: rgb(255,0,0);
+      font: "Noto Sans Mono 3";
+      glyphs: "o";
+    }
+  }
+}

testsuite/gsk/meson.build

@@ -98,6 +98,7 @@ compare_render_tests = [
   'mask-texture-color-alpha',
   'mipmap-generation-later',
   'nested-rounded-clips',
+  'o-from-hell',
   'offscreen-fractional-translate-nogl',
   'offscreen-pixel-alignment-nogl-nocairo',
   'offscreen-pixel-alignment2',