testsuite: Add a test for texture-scale filters

Check that the right filter is chosen and that that filter is
implemented correctly.

The test is disabled for Cairo because Cairo (or rather Pixman)
doesn't follow the filtering specifications for GL/Vulkan and in
particular the nearest filter picks a different pixel.

testsuite/gsk/compare/texture-scale-filters-3d.node

@@ -0,0 +1,30 @@
+texture-scale {
+  bounds: 4 4 24 24;
+  filter: nearest;
+  texture: "texture1" url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAgAAAAICAYAAADED76LAAAAJ0lEQVQYlWNkYPjwnwEPYMInSbqC\
+AwwCDAcYBPCb4HAAlc9Ie0cCAB8uBo20gfbVAAAAAElFTkSuQmCC\
+");
+}
+repeat {
+  bounds: 32 0 32 32;
+  child: texture-scale {
+    bounds: 0 0 1 1;
+    filter: nearest;
+    texture: "texture1";
+  }
+}
+repeat {
+  bounds: 0 32 32 32;
+  child: texture-scale {
+    bounds: 0 0 1 1;
+    texture: "texture1";
+  }
+}
+repeat {
+  bounds: 32 32 32 32;
+  child: texture-scale {
+    bounds: 0 0 1 1;
+    filter: trilinear;
+    texture: "texture1";
+  }
+}

testsuite/gsk/meson.build

@@ -98,6 +98,7 @@ compare_render_tests = [
   'shadow-opacity',
   'shrink-rounded-border',
   'stroke',
+  'texture-scale-filters-3d',
   'texture-scale-magnify-10000x',
   'texture-scale-magnify-rotate',
   'texture-scale-stripes',