[e2e] fix e2e tests

* use new _flowconfig in generator template
* increase sinopia max_body_size
* remove breaking `cd` command from e2e-test.sh

scripts/e2e-sinopia.config.yml

@@ -19,3 +19,5 @@ packages:
 
 logs:
   - {type: file, path: sinopia.log, format: pretty, level: http}
+
+max_body_size: '50mb'

scripts/e2e-test.sh

@@ -70,5 +70,4 @@ flow --retries 10
 
 node ../node_modules/react-native/packager/packager.js --nonPersistent &
 SERVER_PID=$!
-cd iOS
 xctool -scheme EndToEndTest -sdk iphonesimulator test