autotest: print content of sitl /proc/PID/status on death

Mysterious death ofi Copter in CI - add more debug

Tools/autotest/common.py

@@ -6057,6 +6057,11 @@ Also, ignores heartbeats not from our target system'''
             pass
         self.progress("Most recent logfile: %s" % (path, ), send_statustext=send_statustext)
 
+    def progress_file_content(self, filepath):
+        with open(filepath) as f:
+            for line in f:
+                self.progress(line.rstrip())
+
     def run_one_test_attempt(self, test, interact=False, attempt=1, do_fail_list=True):
         '''called by run_one_test to actually run the test in a retry loop'''
         name = test.name
@@ -6112,7 +6117,7 @@ Also, ignores heartbeats not from our target system'''
             ardupilot_alive = True
         except Exception:
             # process is dead
-            self.progress("Not alive after test", send_statustext=False)
+            self.progress("No heartbeat after test", send_statustext=False)
             if self.sitl.isalive():
                 self.progress("pexpect says it is alive")
                 for tool in "dumpstack.sh", "dumpcore.sh":
@@ -6122,6 +6127,15 @@ Also, ignores heartbeats not from our target system'''
                         return False
             else:
                 self.progress("pexpect says it is dead")
+
+            # try dumping the process status file for more information:
+            status_filepath = "/proc/%u/status" % self.sitl.pid
+            self.progress("Checking for status filepath (%s)" % status_filepath)
+            if os.path.exists(status_filepath):
+                self.progress_file_content(status_filepath)
+            else:
+                self.progress("... does not exist")
+
             passed = False
             reset_needed = True