Don't try to remove packages that are not installed.

While building what I thought would be the final 4.22 images I got:

Removing unwanted packages
E: Unable to locate package ^linux-compiler-*
E: Couldn't find any package by glob '^linux-compiler-*'
E: Couldn't find any package by regex '^linux-compiler-*'
E: Unable to locate package ^linux-kbuild-*
E: Couldn't find any package by glob '^linux-kbuild-*'
E: Couldn't find any package by regex '^linux-kbuild-*'
Reading package lists...
Building dependency tree...
Reading state information...
Package 'binutils-mingw-w64-i686' is not installed, so not removed
Package 'binutils-mingw-w64-x86-64' is not installed, so not removed
Package 'binutils-multiarch' is not installed, so not removed
Package 'binutils-doc' is not installed, so not removed
E: Unable to locate package ^linux-compiler-*
E: Couldn't find any package by glob '^linux-compiler-*'
E: Couldn't find any package by regex '^linux-compiler-*'
E: Unable to locate package ^linux-kbuild-*
E: Couldn't find any package by glob '^linux-kbuild-*'
E: Couldn't find any package by regex '^linux-kbuild-*'
E: config/chroot_local-hooks/98-remove_unwanted_packages failed (exit non-zero). You should check for errors.