chg: dev: Use sanitizer.contains() instead of the "in" operator

muon's static analyzer aborts on the four "'address' in sanitizer"
expressions because it cannot typecheck the "in" operator against the
complex combo type it infers for b_sanitize, which makes "muon analyze"
unusable on the whole tree.  Reported upstream as
https://github.com/muon-build/muon/issues/289.

Assisted-by: Claude:claude-fable-5
Merge branch 'mnowak/meson-sanitizer-contains' into 'main'

See merge request isc-projects/bind9!12459