CI: don't increase hypothesis example count with PyPy

PyPy takes way too long in CI

tests/conftest.py

@@ -1,13 +1,20 @@
 import os
+import platform
 
 from hypothesis import settings
 
 
 if "CI" in os.environ:
     # CI can be slow, so be patient
     # Also we can run more tests there
+
+    max_examples = settings.default.max_examples * 5
+    if platform.python_implementation() == "PyPy":
+        # PyPy is too slow
+        max_examples = settings.default.max_examples
+
     settings.register_profile(
         "ci",
         deadline=settings.default.deadline * 10,
-        max_examples=settings.default.max_examples * 5)
+        max_examples=max_examples)
     settings.load_profile("ci")