patch 9.0.0754: 'indentexpr' overrules lisp indenting in one situation

Problem:    'indentexpr' overrules lisp indenting in one situation.
Solution:   Add "else" to keep the lisp indent. (issue #11327)
diff --git a/src/testdir/test_lispindent.vim b/src/testdir/test_lispindent.vim
index 8f2d332..3c8660e 100644
--- a/src/testdir/test_lispindent.vim
+++ b/src/testdir/test_lispindent.vim
@@ -91,6 +91,17 @@
   call assert_equal(-1, lispindent(-1))
 endfunc
 
+func Test_lispindent_with_indentexpr()
+  enew
+  setl ai lisp nocin indentexpr=11
+  exe "normal a(x\<CR>1\<CR>2)\<Esc>"
+  let expected = ['(x', '  1', '  2)']
+  call assert_equal(expected, getline(1, 3))
+  normal 1G=G
+  call assert_equal(expected, getline(1, 3))
+  bwipe!
+endfunc
+
 func Test_lisp_indent_works()
   " This was reading beyond the end of the line
   new