Let parsed_parameters can get '_' correctly from instance-parameter:configuration

When there has no '_', SlapOS will report 'configuration._', was not defined.
And there has '!py!' prefix in the instance-parameter. And we also need to take care the key of
'_' use double quotes instead single quotes. So use ast.literal_eval instead the json.dump

software/jstestnode/runTestSuite.in

@@ -50,8 +50,11 @@ def main():
   args = parser.parse_args()
 
   import json
-  parsed_parameters = json.loads('$${instance-parameter:configuration._}')
-
+  no_py_prefix = '''$${instance-parameter:configuration}'''[4:] # The input_str has "!py!" prefix.
+  json_style_para = no_py_prefix.replace('\'', '\"')
+  parameters = json.loads(json_style_para)
+  parsed_parameters = json.loads(parameters.get('_', '{}'))
+  print(parsed_parameters)
 
   if not getattr(args, 'target', None):
     args.target = parsed_parameters.get('target', 'firefox')
@@ -87,7 +90,8 @@ def main():
     ##########################
     
     is_appium = False
-    
+ 
+
     if args.target == 'firefox':
       firefox_capabilities = webdriver.common.desired_capabilities.DesiredCapabilities.FIREFOX
       firefox_capabilities['marionette'] = True

software/jstestnode/software.cfg

@@ -107,7 +107,7 @@ mode = 0644
 [template-runTestSuite]
 recipe = slapos.recipe.template
 url = ${:_profile_base_location_}/runTestSuite.in
-md5sum = fcf15b2a90340e0afe8f8b9921a4ffae
+md5sum = ac50975607770280fd988e307ef93cfe
 output = ${buildout:directory}/runTestSuite.in
 mode = 0644