Add a benchmark for import time of importlib_metadata.

Relies on pytest-perf 0.17 for import time testing.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: jaraco

exercises.py

@@ -52,3 +52,8 @@ def normalize_perf():
     import importlib_metadata  # end warmup
 
     importlib_metadata.Prepared.normalize('sample')
+
+
+def import_time():
+    "import"
+    import importlib_metadata  # noqa: F401

pyproject.toml

@@ -38,7 +38,7 @@ test = [
 	# local
 	"packaging",
 	"pyfakefs",
-	"pytest-perf >= 0.16",
+	"pytest-perf >= 0.17",
 ]
 
 doc = [