Add use-after-destruction error messages
Add use-after-destruction error messages

Summary: `ConcurrentHashMap` has a `DCHECK` for use-after-destruction. One of these has a comment explaining what it's for, but `DCHECK` supports taking a message to show the user. Make it a message.

Reviewed By: yfeldblum, magedm

Differential Revision: D28609176

fbshipit-source-id: ea6e57b7650ad597f45ea3efc2fa0fb62d5de40e

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