Revert "Syndicate, test and fix base64 implementation"

This reverts commit 5a1958f2673f8c771e406a7e309e160b432c9a79.

This change broke the UBSan build bots. See
https://reviews.llvm.org/D75057 for more information.

GitOrigin-RevId: 49684f9db5c3e00a7739bc60d1d7aa9bb1c780d9
1 file changed