Add Baseline profile rules for `androidx.startup`.
Add Baseline profile rules for `androidx.startup`.

* Ensures that `AppInitializer` is optimized.

Test: ./gradlew :startup:integration-tests:test-app:assembleRelease
Change-Id: Iab1177c9f499d8716ddc05878ada9a7af30b3ffc

androidx/androidx,androidx/androidx,androidx/androidx,AndroidX/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx,androidx/androidx,AndroidX/androidx,AndroidX/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,AndroidX/androidx,AndroidX/androidx,AndroidX/androidx,androidx/androidx