Android Google Pixel 4 and Pixel 3 reference devices to RTA for Qt 6

Who
As a Qt Android developer I want to verify my implementation before delivering it to community and customers with appropriate devices.

What
Google uses in their pre-launch tests for Android version 28 Pixel 3 and for 29 Pixel 4 reference devices. Qt 6 shall support Android 28 as build-time and 23 as runtime. 
Android target architectures and compilers: armeabi-v7a, arm64-v8a, x86, x86_64 (no changes) and compiler Clang 9 (no changes, same since r21). 
Android hosts architectures and compilers: Windows MinGW 8.1 (change), other platforms (no changes)
 

https://intranet.qt.io/display/QTRD/Discussion+of+Qt+6.0%2C+6.1%2C+6.2+Supported+Functionality

Why
For Qt5 to Qt6 there happens a BC break. There is significant changes to be done for Platforms Area e.g. https://bugreports.qt.io/browse/QTBUG-80233 and https://bugreports.qt.io/browse/QTBUG-84382
At the moment the RTA testing is done manually (correct?) against Samsung S4 (Android 9) tab and Pixel C (Android 8?). RTA team has Pixel 3a, but it's not in RTA yet.

Definition of Done (DoD)
Google reference devices for Android 9 and 10 are added to RTA. RTA executes automatic tests for Android. RTA provides results for both devices. Automatic tests are meaningful and do not provide false positives nor false negatives. First of such test could be a booting of the device.

More info

• https://www.gsmarena.com/google_pixel_4-9896.php
• https://www.gsmarena.com/google_pixel_3-9256.php
• https://www.gsmarena.com/google_pixel_3a-9408.php
• [^image-2020-05-04-10-19-48-904.png] (Google list)
• https://developer.android.com/about/versions/marshmallow/android-6.0