Port building Schema from AST benchmark

From src/utilities/__tests__/buildASTSchema-benchmark.js

Author: ktosiek

tests/benchmarks/test_build_ast_schema.py

@@ -0,0 +1,12 @@
+from graphql import parse, build_ast_schema, GraphQLSchema
+
+# noinspection PyUnresolvedReferences
+from ..fixtures import big_schema_sdl  # noqa: F401
+
+
+def test_building_ast_of_big_schema(benchmark, big_schema_sdl):  # noqa: F811
+    schema_ast = parse(big_schema_sdl)
+    schema: GraphQLSchema = benchmark(
+        lambda: build_ast_schema(schema_ast, assume_valid=True)
+    )
+    assert schema.query_type is not None