sanitycheck: support pre/post flash scripts

This is needed when a board needs to be reset using an external commands
or tools that are not part of the flash command. For example, power
reset or by poking a GPIO header on the board using external wiring.

add post_flash/pre_flash to the platform section in the hardware map.
For example:

- available: true
  connected: true
  id: OSHW000032254e4500128002ab98002784d1000097969900
  platform: reel_board
  post_script: /tmp/post_flash.sh
  pre_script: /tmp/pre_flash.sh
  product: DAPLink CMSIS-DAP
  runner: pyocd
  serial: /dev/ttyACM11

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

scripts/sanitycheck

@@ -759,6 +759,21 @@ class DeviceHandler(Handler):
         read_pipe, write_pipe = os.pipe()
         start_time = time.time()
 
+
+        pre_script = hardware.get('pre_script')
+        post_script = hardware.get('post_script')
+
+        if pre_script:
+            with subprocess.Popen(pre_script, stderr=subprocess.PIPE, stdout=subprocess.PIPE) as proc:
+                try:
+                    (stdout, stderr) = proc.communicate(timeout=30)
+                    logger.debug(stdout.decode())
+
+                except subprocess.TimeoutExpired:
+                    proc.kill()
+                    (stdout, stderr) = proc.communicate()
+                    logger.error("{} timed out".format(post_script))
+
         t = threading.Thread(target=self.monitor_serial, daemon=True,
                              args=(ser, read_pipe, harness))
         t.start()
@@ -812,6 +827,17 @@ class DeviceHandler(Handler):
         else:
             self.set_state(out_state, handler_time)
 
+        if post_script:
+            with subprocess.Popen(post_script, stderr=subprocess.PIPE, stdout=subprocess.PIPE) as proc:
+                try:
+                    (stdout, stderr) = proc.communicate(timeout=30)
+                    logger.debug(stdout.decode())
+
+                except subprocess.TimeoutExpired:
+                    proc.kill()
+                    (stdout, stderr) = proc.communicate()
+                    logger.error("{} timed out".format(post_script))
+
         self.make_device_available(serial_device)
 
         self.record(harness)