patch 8.0.0853: crash when running terminal with unknown command

Problem:    Crash when running terminal with unknown command.
Solution:   Check "term" not to be NULL. (Yasuhiro Matsumoto, closes #1932)

src/terminal.c

@@ -629,7 +629,8 @@ term_job_running(term_T *term)
 {
     /* Also consider the job finished when the channel is closed, to avoid a
      * race condition when updating the title. */
-    return term->tl_job != NULL
+    return term != NULL
+	&& term->tl_job != NULL
 	&& term->tl_job->jv_status == JOB_STARTED
 	&& channel_is_open(term->tl_job->jv_channel);
 }

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    853,
 /**/
     852,
 /**/