Fix review issues: boolean comparison, missing trigger, constants

- Fix benchmarks CI condition: 'true' not 'True' (jq outputs lowercase)
- Add script/setup_codspeed_lib.py to benchmark infrastructure triggers
- Extract BENCHMARK_INFRASTRUCTURE_FILES and BENCHMARKS_COMPONENTS_PATH
  as top-level constants in determine-jobs.py
- Fix extra_include_dirs docstring

script/test_helpers.py

@@ -328,8 +328,8 @@ def build_and_run(
         label: Label for log messages
         build_only: If True, print binary path and return without running
         extra_run_args: Extra arguments to pass to the binary
-        extra_include_dirs: Additional directories (relative to tests_dir)
-            whose .cpp files should be compiled
+        extra_include_dirs: Additional directories whose .cpp files
+            should be compiled (resolved relative to tests_dir if possible)
 
     Returns:
         Exit code