ci: Fixes after Debian release#969

Merged

jonasnick merged 2 commits intobitcoin-core:masterfrom real-or-random:202108-ci-bullseye

Aug 20, 2021

+7-5

Commits on Aug 19, 2021

ci: Install libasan6 (instead of 5) after Debian upgrade
real-or-random
committed
tests: Rewrite code to circument potential bug in clang
real-or-random
committed