patch 9.0.1377: job_status() may return "dead" if the process parent changed

Problem:    job_status() may return "dead" if the process parent changed.
Solution:   Call mch_process_running() to check if the job is still alive.

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1377,
 /**/
     1376,
 /**/