patch 8.2.0195: some tests fail when run in the GUI

Problem:    Some tests fail when run in the GUI.
Solution:   Make sure the window width is enough.  In the GUI run terminal Vim
            in the terminal, if possible.
diff --git a/src/testdir/test_terminal.vim b/src/testdir/test_terminal.vim
index 7fda9f6..3ff5db6 100644
--- a/src/testdir/test_terminal.vim
+++ b/src/testdir/test_terminal.vim
@@ -2331,7 +2331,7 @@
     in a popup window
   END
   call writefile(text, 'Xtext')
-  let cmd = GetVimCommandClean()
+  let cmd = GetVimCommandCleanTerm()
   let lines = [
 	\ 'call setline(1, range(20))',
 	\ 'hi PopTerm ctermbg=grey',