ci/freedreno: Restart the run if cheza spontenously reboots.

Occasionally (once every couple weeks?) a cheza reboots mid run, around a
GPU fault.  Detect that and do an internal retry instead of failing out
the job.

Closes: #5388
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13181>

.gitlab-ci/bare-metal/cros_servo_run.py

@@ -145,6 +145,11 @@ class CrosServoRun:
                 self.print_error("Detected cheza power management bus error, restarting run...")
                 return 2
 
+            if re.search("coreboot.*bootblock starting", line):
+                self.print_error(
+                    "Detected spontaneous reboot, restarting run...")
+                return 2
+
             result = re.search("hwci: mesa: (\S*)", line)
             if result:
                 if result.group(1) == "pass":