Revert "core-all-system-modules: Restrict visibility."

This reverts commit 5a63e0e221801b06db425b3f23942d8a3a3adf61.

Reason for revert: Neil suggested a better approach in a review comment on https://android-review.googlesource.com/c/platform/libcore/+/971162 , so I'm reverting this CL and then implementing the other approach.

Test: Treehugger
Change-Id: I057f9141a034338bde9d2a56cb14b796adbbdf09
1 file changed