Align detection of nocheck with debhelper

Debhelper only recognizes "nocheck" as a separate word, not as part of a bigger word. See https://salsa.debian.org/debian/debhelper/-/blob/main/lib/Debian/Debhelper/Dh_Lib.pm#L2667 and https://salsa.debian.org/debian/debhelper/-/blob/main/lib/Debian/Debhelper/Dh_Lib.pm#L2688.

This MR makes it possible to use build options and/or profiles containing "nocheck".

I ran into this while using a custom build profile containing "nocheck" to disable a long running part of a larger test suite for faster iterating.