Move to using AGP 3.0.0 Beta 2.
Move to using AGP 3.0.0 Beta 2.

Bug: 64692907
Test: ./gradlew buildOnServer for support library
Change-Id: I51538d5954413db7012765a253c931591aa68dec

androidx/androidx,aosp-mirror/platform_frameworks_support,AndroidX/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,aosp-mirror/platform_frameworks_support,AndroidX/androidx,AndroidX/androidx,AndroidX/androidx,aosp-mirror/platform_frameworks_support,aosp-mirror/platform_frameworks_support,androidx/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx,androidx/androidx,aosp-mirror/platform_frameworks_support,AndroidX/androidx,AndroidX/androidx