[gtk] Disable the label-background reftest

[Matthias Clasen <matthiasc src gnome org>]

commit eba9cd8775eafa7d94f3823fdc69b6f0c5f57cc9
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Mar 30 07:42:18 2021 -0400

    Disable the label-background reftest
    
    It makes assumptions about text positioning that are
    not holding with subpixel positioning. There is no
    guarantee that the next word in a multi-word text
    starts on an even pixel boundary, as it does when
    you break the text into multiple, separately rendered
    blocks.

 testsuite/reftests/meson.build | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)
---
diff --git a/testsuite/reftests/meson.build b/testsuite/reftests/meson.build
index 0df2c5469a..42c59e2026 100644
--- a/testsuite/reftests/meson.build
+++ b/testsuite/reftests/meson.build
@@ -287,9 +287,11 @@ testdata = [
   'label-attribute-preference.css',
   'label-attribute-preference.ref.ui',
   'label-attribute-preference.ui',
-  'label-background.css',
-  'label-background.ref.ui',
-  'label-background.ui',
+  # makes assumptions about text positioning that are not
+  # valid with subpixel positioning
+  #'label-background.css',
+  #'label-background.ref.ui',
+  #'label-background.ui',
   'label-box-shadow-clip.css',
   'label-box-shadow-clip.ref.ui',
   'label-box-shadow-clip.ui',