[gtk] (6 commits) Non-fast-forward update to branch modern-testsuite

[Benjamin Otte <otte src gnome org>]

The branch 'modern-testsuite' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  8ef230c... reftests: Use the default (aka NGL) renderer
  c556c31... ngl: Improve shortcuts for shadow nodes
  a1d02c4... ngl: Avoid offscreens in more cases
  e9de8a0... rendernodeparser: Handle is_color attribute for glyphs
  86b4cd1... reftest: Plug a memory leak
  91377d5... reftests: Don't use 0.5 for color values

Commits added to the branch:

  c9efd62... ngl: Improve shortcuts for shadow nodes
  3e46b23... ngl: Avoid offscreens in more cases
  efbe7f9... rendernodeparser: Handle is_color attribute for glyphs
  1c01c6d... reftests: Use colors without rounding errors
  9eb4b10... reftests: XFAIL border-half-pixel test
  c17ad26... reftests: Use the default (aka NGL) renderer