[gtksourceview/wip/chergert/gsv-gtk4] build: remove old completion model test

[Christian Hergert <chergert src gnome org>]

commit 0848a14a9146b3d550a693f72dfd08a8c164fefd
Author: Christian Hergert <chergert redhat com>
Date:   Sun Aug 30 08:44:42 2020 -0700

    build: remove old completion model test

 testsuite/meson.build             |   1 -
 testsuite/test-completion-model.c | 642 --------------------------------------
 2 files changed, 643 deletions(-)
---
diff --git a/testsuite/meson.build b/testsuite/meson.build
index 83e9991e8..8f1501670 100644
--- a/testsuite/meson.build
+++ b/testsuite/meson.build
@@ -18,7 +18,6 @@ testsuite_sources = [
   ['test-buffer'],
   ['test-buffer-input-stream'],
   ['test-buffer-output-stream'],
-  ['test-completion-model'],
   ['test-completion-words'],
   ['test-encoding'],
   ['test-file-loader'],