Revert^2 "Use ConcurrentHashMap to make private maps thread safe"

This reverts commit f480cf371a199c92eee26adebafc2c72a41129f0.

Reason for revert: not the cause of b/367736714

Change-Id: If9b400c5474d9ec51f51f1de86c80b9337857fac
2 files changed