Revert "[res] Better modification time resolution in Idmap"

This reverts commit fff1d48f.

Reason for revert: <Potential culprit for b/365676142  - verifying through ABTD before revert submission. This is part of the standard investigation process, and does not mean your CL will be reverted.>

Change-Id: I6b0a0bd67a14e4738a8cd64be2214840d02eee3f