Vim 8.1 release

Update version number and information.  Fix a couple of tests.
diff --git a/src/vim.def b/src/vim.def
index 7ae7f8d..e0368fc 100644
--- a/src/vim.def
+++ b/src/vim.def
@@ -1,4 +1,4 @@
 CODE PRELOAD EXECUTEONLY
 DATA MULTIPLE SHARED
-DESCRIPTION 'Vim 8.0'
+DESCRIPTION 'Vim 8.1'
 HEAPSIZE 0,0