patch 8.2.4677: the Athena GUI support is outdated

Problem:    The Athena GUI support is outdated.
Solution:   Remove the Athena GUI code.
diff --git a/src/testdir/test_quotestar.vim b/src/testdir/test_quotestar.vim
index b669019..1d26942 100644
--- a/src/testdir/test_quotestar.vim
+++ b/src/testdir/test_quotestar.vim
@@ -98,7 +98,7 @@
 
     " Running in a terminal and the GUI is available: Tell the server to open
     " the GUI and check that the remote command still works.
-    if has('gui_athena') || has('gui_motif')
+    if has('gui_motif')
       " For those GUIs, ignore the 'failed to create input context' error.
       call remote_send(name, ":call test_ignore_error('E285') | gui -f\<CR>")
     else