Merge #11252: [P2P] When clearing addrman clear mapInfo and mapAddr.

Summary:
b86a42077 when clearing addrman clear mapInfo and mapAddr (Gregory Sanders)

Pull request description:

Power failure on my machine resulted in a corrupted addrman that would hit bad assertions when trying to serialize the "cleared" addrman to disk: https://github.com/bitcoin/bitcoin/blob/6866b4912b8013ed748d12250209f7079a3c92e6/src/addrman.h#L320

Tree-SHA512: 07ca8b6cbd88407e5f3f0dccb346ae31bd1392f4210b2d5c5647c853986bfec95cf70240b92bafdc61b90e452a5d8315962738d10c10c2b53fdabff10503d05a

Backport Core PR 11252
https://github.com/bitcoin/bitcoin/pull/11252/files

Test Plan: ninja check

Reviewers: deadalnix, Fabien, #bitcoin_abc

Reviewed By: Fabien, #bitcoin_abc

Differential Revision: https://reviews.bitcoinabc.org/D2944