Use stdlib native modules in benchmarks (#6792)

Change benchmark interpreter from without_stdlib to with_init to load
Rust-optimized native modules like _json, ensuring benchmarks measure
actual optimized performance rather than pure Python fallbacks.

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Cargo.toml

@@ -54,6 +54,7 @@ rustyline = { workspace = true }
 [dev-dependencies]
 criterion = { workspace = true }
 pyo3 = { version = "0.27", features = ["auto-initialize"] }
+rustpython-stdlib = { workspace = true }
 
 [[bench]]
 name = "execution"

benches/execution.rs

@@ -24,7 +24,10 @@ fn bench_rustpython_code(b: &mut Bencher, name: &str, source: &str) {
     settings.path_list.push("Lib/".to_string());
     settings.write_bytecode = false;
     settings.user_site_directory = false;
-    Interpreter::without_stdlib(settings).enter(|vm| {
+    Interpreter::with_init(settings, |vm| {
+        vm.add_native_modules(rustpython_stdlib::get_module_inits());
+    })
+    .enter(|vm| {
         // Note: bench_cpython is both compiling and executing the code.
         // As such we compile the code in the benchmark loop as well.
         b.iter(|| {