tns preview - app is refreshed on ios devices when changing android specific files #4075

Environment

• CLI: 5.0 RC

When changing platform specific files app is refreshed in preview on all connected devices (even from other platform).

Steps:

1. tns create TestApp --js
2. Add platform specific files. For example main-view-model.android.js and main-view-model.android.ios.js
3. tns preview
4. Scan the QR code on android and ios
5. Change only main-view-model.android.js and save
   Expected : only android devices are refreshed and changes are synced.
   Actual: ios devices are refreshed also (the changes are synced correctly only on android)

Also error is shown in the log when adding platform specific files:

1. tns create TestApp --js
2. tns preview
3. Scan the QR code on android and ios
4. Add new test.android.js file to the project

The change is synced for android but there is also error for ios :
Unable to apply changes for platform ios. Error is: Error: ENOENT: no such file or directory, open '/Users/TestProjects/TestApp/platforms/ios/prev/app/test.js', {
"errno": -2,
"code": "ENOENT",
"syscall": "open",
"path": "/Users/TestProjects/TestApp/platforms/ios/prev/app/test.js"
}.