scripted-diff: Rename m_last_send and m_last_recv

Summary:

-BEGIN VERIFY SCRIPT-

ren() { sed -i "s/\<$1\>/$2/g" $(git grep -l "$1" ./src) ; }

ren nLastSend m_last_send
ren nLastRecv m_last_recv

-END VERIFY SCRIPT-

This is a backport of core#19499 [1/2]
https://github.com/bitcoin/bitcoin/pull/19499/commits/fa6d5a238d2c94440105ddd4f1554f85659d6c5b

Test Plan: ninja all check-all

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D10954