patch 8.0.1623: terminal kill tests are flaky

Problem:    Terminal kill tests are flaky.
Solution:   Instead of running Vim in a terminal, run it as a normal command.

src/version.c

@@ -766,6 +766,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1623,
 /**/
     1622,
 /**/