[tests] Add CodSpeed benchmark for compiled-config cache fast path (#16402)

Co-authored-by: pre-commit-ci-lite[bot] <117423508+pre-commit-ci-lite[bot]@users.noreply.github.com>

requirements_test.txt

@@ -13,5 +13,10 @@ pytest-xdist==3.8.0
 asyncmock==0.4.2
 hypothesis==6.92.1
 
+# CodSpeed benchmarks under tests/benchmarks/python/
+# (skipped via pytest.importorskip when missing -- only required for the
+# benchmarks job in .github/workflows/ci.yml)
+pytest-codspeed==5.0.1
+
 # Used by the import-time regression check (.github/workflows/ci.yml → import-time job)
 importtime-waterfall==1.0.0