Meta: Verify all AK test files are listed in CMake

Problem:
- It is possible for a new test file to be added to the `AK/Tests`
  directory without being added to the corresponding
  `CMakeLists.txt`. This results in the tests not being run.

Solution:
- As part of CI linting, verify that all the `AK/Tests/Test*.cpp`
  files are mentioned in the `CMakeLists.txt`.

Meta/lint-ci.sh

@@ -6,6 +6,7 @@ script_path=$(cd -P -- "$(dirname -- "$0")" && pwd -P)
 cd "${script_path}/.." || exit 1
 
 for cmd in \
+        Meta/check-ak-test-files.sh \
         Meta/check-debug-flags.sh \
         Meta/check-style.sh \
         Meta/lint-executable-resources.sh \