CI build gcc-9-release-i686 is broken

[mjjbell]

https://github.com/Project-OSRM/osrm-backend/runs/4360200799?check_suite_focus=true

/usr/bin/ld.gold: error: /usr/lib/x86_64-linux-gnu/libexpat.so: incompatible target

cmake is finding the 64 bit version of the Expat library instead of the 32 bit version.

During the CI migration to Github Actions, a bug was introduced such that Mason cmake is not being added to the PATH environment variable correctly, so it defaults to the cmake installed in the OS environment. This was recently auto-updated to version 3.22 in the Ubuntu Focal workers, leading to the regression in unrelated changes such as #6162

Fixing the use of Mason cmake also fails as it requires libssl 1.0 as a dependency, whilst the Ubuntu Focal runners are on the newer libssl 1.1

So the options to fix CI are to:

1. Understand the change in cmake 3.22 that leads to 32 bit libraries not being detected correctly and correct our CMakeLists.txt
2. Install libssl 1.0 on the Ubuntu CI workers
3. Add libssl 1.1 support to Mason cmake

1 seems like the preferred choice here.