Measure print/visit performance

Note that the performance was already optimized in Python.

Replicates graphql/graphql-js@31bf28f4

Author: Cito

tests/benchmarks/test_print.py

@@ -0,0 +1,11 @@
+from graphql import parse, print_ast
+
+from ..fixtures import kitchen_sink_query  # noqa: F401
+
+
+def test_print_kitchen_sink(benchmark, kitchen_sink_query):  # noqa: F811
+    document = parse(
+        kitchen_sink_query, experimental_client_controlled_nullability=True
+    )
+    result = benchmark(lambda: print_ast(document))
+    assert isinstance(result, str)