Add AGP 3.0.0 beta 2 to prebuilts.

Bug: 64692907
Test: ./gradlew buildOnServer for support library.
Change-Id: If3a20f8758c3a7e17e919e9320502f8233ef43ba
495 files changed
tree: 50f2b703f2cdcdd273b54b9b7a300cce6fd0aa41
  1. com/
  2. net/
  3. org/
  4. .gitignore