patch 8.1.2274: newlines in 'balloonexpr' result only work in the GUI

Problem:    Newlines in 'balloonexpr' result only work in the GUI.
Solution:   Also recognize newlines in the terminal. (closes #5193)
diff --git a/src/testdir/test_balloon.vim b/src/testdir/test_balloon.vim
index e4ee855..f32b73c 100644
--- a/src/testdir/test_balloon.vim
+++ b/src/testdir/test_balloon.vim
@@ -12,7 +12,7 @@
   call setline(1, ["one one one", "two tXo two", "three three three"])
   set balloonevalterm balloonexpr=MyBalloonExpr() balloondelay=100
   func MyBalloonExpr()
-    return "line " .. v:beval_lnum .. " column " .. v:beval_col .. ": " .. v:beval_text
+    return "line " .. v:beval_lnum .. " column " .. v:beval_col .. ":\n" .. v:beval_text
   endfun
   redraw
 [CODE]