Added commands to kill crosvm and run_cvd processes (#4632)

Adds 'pkill crosvm' and 'pkill run_cvd' commands to
stop_cuttlefish_device function to ensure complete shutdown of
cuttlefish device.

Author: aditya-wazir

src/clusterfuzz/_internal/platforms/android/adb.py

@@ -52,6 +52,8 @@
 GET_DEVICE_STATE_TIMEOUT = 20
 STOP_CVD_WAIT = 20
 LAUNCH_CVD_TIMEOUT = 2700
+CMD_KILL_CROSVM = 'pkill crosvm'
+CMD_KILL_RUN_CVD = 'pkill run_cvd'
 
 # Output patterns to parse "lsusb" output.
 LSUSB_BUS_RE = re.compile(r'Bus\s+(\d+)\s+Device\s+(\d+):.*')
@@ -448,6 +450,11 @@ def stop_cuttlefish_device():
         stop_cvd_cmd, timeout=RECOVERY_CMD_TIMEOUT, on_cuttlefish_host=True)
     time.sleep(STOP_CVD_WAIT)
 
+  execute_command(
+      CMD_KILL_CROSVM, timeout=RECOVERY_CMD_TIMEOUT, on_cuttlefish_host=True)
+  execute_command(
+      CMD_KILL_RUN_CVD, timeout=RECOVERY_CMD_TIMEOUT, on_cuttlefish_host=True)
+
 
 def restart_cuttlefish_device():
   """Restarts the cuttlefish device."""