Revert "remove unneeded dontwarn settings"

This reverts commit 59570d1e64.

Reason for revert: we still need these flags

Change-Id: I8caa6350f0b62e6aa2a190e128d5ce7d8f849ea8

core/proguard_basic_keeps.flags

@@ -83,14 +83,13 @@
 # 1) runtime-visible annotations will still be kept, and 2) compile-time
 # annotations are stripped by R8 anyway.
 # Note: The ** prefix is used to accommodate jarjar repackaging.
-# TODO(b/266561579): Remove this exemptions after resolving jarjar-ed transitive libs
+# TODO(b/242088131): Remove these exemptions after resolving transitive libs
+# dependencies that are provided to R8.
 -dontwarn **android**.annotation*.**
-
-# These classes generate warnings of the kind `Library class extends program class`
-# because some apps have deps that statically include the same libraries as the app,
-# and r8 complains that a library is implementing a class provided by the app (the "program").
--dontwarn com.google.protobuf.**
--dontwarn kotlin.reflect.jvm.internal.ReflectionFactoryImpl
+-dontwarn **com.google.errorprone.annotations.**
+-dontwarn javax.annotation.**
+-dontwarn org.checkerframework.**
+-dontwarn org.jetbrains.annotations.**
 
 # Less spammy.
 -dontnote