Better marking of visited tiles. #2161

Job	Run time
Documentation	13m 32s
windows-2019 / Debug	4m 44s
Quick Checks	8s
windows-2019 / RelWithDebInfo	4m 43s
ubuntu-latest / gcc / Debug	3m 16s
windows-2022 / Debug	5m 5s
ubuntu-latest / gcc / RelWithDebInfo	7m 38s
windows-2022 / RelWithDebInfo	4m 57s
ubuntu-20.04 / clang / Debug	3m 35s
ubuntu-20.04 / clang / RelWithDebInfo	3m 26s
macos-12 / clang / Debug	6m 13s
macos-12 / clang / RelWithDebInfo	3m 58s
	1h 1m 15s

Provide feedback