patch 8.2.1067: expression "!expr->func()" does not work

Problem:    Expression "!expr->func()" does not work.
Solution:   Apply plus and minus earlier. (closes #6348)
diff --git a/src/testdir/test_expr.vim b/src/testdir/test_expr.vim
index ec73aea..c5dd1f3 100644
--- a/src/testdir/test_expr.vim
+++ b/src/testdir/test_expr.vim
@@ -110,6 +110,13 @@
   call assert_fails('echo "\<C-">')
 endfunc
 
+func Test_method_with_prefix()
+  call assert_equal(1, !range(5)->empty())
+  call assert_equal([0, 1, 2], --3->range())
+  call assert_equal(0, !-3)
+  call assert_equal(1, !+-+0)
+endfunc
+
 func Test_option_value()
   " boolean
   set bri