patch 8.1.2338: using Visual mark sith :s gives E20 if not set

Problem:    Using Visual mark sith :s gives E20 if not set.
Solution:   Ignore errors when handling 'incsearch'. (closes #3837)
diff --git a/src/testdir/test_search.vim b/src/testdir/test_search.vim
index 190755a..1876713 100644
--- a/src/testdir/test_search.vim
+++ b/src/testdir/test_search.vim
@@ -983,6 +983,19 @@
   call VerifyScreenDump(buf, 'Test_incsearch_substitute_12', {})
   call term_sendkeys(buf, "\<Esc>")
   call VerifyScreenDump(buf, 'Test_incsearch_substitute_13', {})
+  call term_sendkeys(buf, ":%bwipe!\<CR>")
+  call term_sendkeys(buf, ":only!\<CR>")
+
+  "  get :'<,'>s command in history
+  call term_sendkeys(buf, ":set cmdheight=2\<CR>")
+  call term_sendkeys(buf, "aasdfasdf\<Esc>")
+  call term_sendkeys(buf, "V:s/a/b/g\<CR>")
+  " Using '<,'> does not give E20
+  call term_sendkeys(buf, ":new\<CR>")
+  call term_sendkeys(buf, "aasdfasdf\<Esc>")
+  call term_sendkeys(buf, ":\<Up>\<Up>")
+  call VerifyScreenDump(buf, 'Test_incsearch_substitute_14', {})
+  call term_sendkeys(buf, "<Esc>")
 
   call StopVimInTerminal(buf)
   call delete('Xis_subst_script')