Add com.android.cronet APEX and org.chromium.net.cronet to base_system.

com.android.cronet will be shipped as a mainline
module in APEX format.

org.chromium.net.cronet is a java_sdk_library used to provide
Cronet API to apps.

Bug: 139397529
Test: Built and installed apex on device
Change-Id: Icff7ded02e360f2df9dfe3ac7185cf7f0034d014