[6_1_X][TIMOB-14742] Android: Fixed window/view "backgroundImage" assignment where it loads the same image 4 times.

[jquick-axway]

JIRA: https://jira.appcelerator.org/browse/TIMOB-14742

This is a back-port of approved PR #8960.
It is needed by upcoming 6.1.x PRs related to image loading.

Note:
Titanium no longer prints each image it's loading to the Android log. So, QE is unable to verify that the image is loading just once or multiple times anymore. But please run the below test to verify that "backgroundImage" before still works for single image backgrounds and multi-state backgrounds.

Testing:

1. Build and run "KitchenSink" app for Android.
2. Tap "Button" item in the list.
3. Tap the "CLICK ME" button several times to verify it changes state like before.
4. Tap the "Back" button.
5. Tap the "Buttons States" item in the list.
6. Tap the "CLICK ME" button several times to verify it changes state like before.

[longton95]

FR passed.

Tested using the test case above, the test case performs as expected and works as before.

ENV

SDK Version : Local 6.2.0, 6.1.0
Mac OS Version : 10.12.4
Appc CLI : 6.2.1
Appc NPM : 4.2.9
Node : v4.6.0
Device: Nexus 5x(6.0.1) Pixel XL(7.1.2)
Emulator: (6.0), (4.4.2)

[hansemannn]

Moving out of 6.1.0, will do it in 6.2.0 to have more space to test.