Migrate CI to Ubuntu 24

[goatgoose]

Problem:

Currently, the vast majority of the Codebuild CI jobs use a Ubuntu 18 image:

s2n-tls/codebuild/spec/buildspec_generalbatch.yml

Line 22 in 1ed5624

image: 024603541914.dkr.ecr.us-west-2.amazonaws.com/docker:ubuntu18codebuild

This includes many of the unit test jobs that test combinations of compilers and libcryptos, and the integration test jobs.

In addition to adding a simple unit test job to Ubuntu 24 (#4529), all of the existing unit test combinations and the integration tests should be moved to Ubuntu 24. This will allow newer compiler versions to be more easily tested.

Solution:

Migrate the ubuntu 18 CI image to Ubuntu 24.

[dougch]

As with Arm/nix, tools like sslyze won't be simple to bring forward. Unit test runs should be trivial to get running with minor updates to the install_ubuntu_deps script.

[boquan-fang]

Pedantic Valgrind check will report still reachable errors for s2n_self_talk_ktls_test on Ubuntu 24. Hence, the new CTest memcheck still uses Ubuntu 18 for pendantic Valgrind check. See the end of this codebuild job for the exact issue.

[boquan-fang]

PR#4852 has fixed the still reachable memory loss for pedantic check on Ubuntu 24. Valgrind checks has been migrated from Ubuntu 18 to Ubuntu 22 and 24. We keep two Valgrind checks on Ubuntu 22, since that platform hasn't been deprecated.