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.
diff --git a/src/version.c b/src/version.c
index 022b9ff..a9cf30e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1377,
+/**/
     1376,
 /**/
     1375,