patch 8.0.0822: Test_with_partial_callback is a tiny bit flaky

Problem:    Test_with_partial_callback is a tiny bit flaky.
Solution:   Add it to the list of flaky tests.

src/testdir/runtest.vim

@@ -233,6 +233,7 @@ let s:flaky = [
       \ 'Test_quoteplus()',
       \ 'Test_quotestar()',
       \ 'Test_reltime()',
+      \ 'Test_with_partial_callback()',
       \ ]
 
 " Locate Test_ functions and execute them.

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    822,
 /**/
     821,
 /**/