patch 9.1.1370: CI Tests favor GTK2 over GTK3

Problem:  CI Tests favor GTK2 over GTK3
Solution: Install GTK3 dependencies and debug packages for CI workflows,
          update ASAN suppression list, update required dependency
          checks for the tests (Drew Vogel)

closes: #17253

Signed-off-by: Drew Vogel <dvogel@github>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_cursor_func.vim b/src/testdir/test_cursor_func.vim
index 8766f97..1fd6b5f 100644
--- a/src/testdir/test_cursor_func.vim
+++ b/src/testdir/test_cursor_func.vim
@@ -92,6 +92,10 @@
 endfunc
 
 func Test_screenpos()
+  if has('gui_running')
+    set lines=25
+    set columns=78
+  endif
   rightbelow new
   rightbelow 20vsplit
   call setline(1, ["\tsome text", "long wrapping line here", "next line"])