Ignore node: and cloudflare: modules when collecting modules (#569)

Previously, Miniflare would complain when specifying a `script`/
`scriptPath` that used `node:`/`cloudflare:` imports with
`modules: true` set. This change updates Miniflare's module collector
to ignore them, as they're automatically included by `workerd`.

packages/miniflare/src/plugins/core/modules.ts

@@ -243,6 +243,12 @@ ${dim(modulesConfig)}`;
 			throw new MiniflareCoreError("ERR_MODULE_DYNAMIC_SPEC", message);
 		}
 		const spec = specExpression.value;
+
+		// `node:` and `cloudflare:` imports don't need to be included explicitly
+		if (spec.startsWith("node:") || spec.startsWith("cloudflare:")) {
+			return;
+		}
+
 		const identifier = path.resolve(path.dirname(referencingPath), spec);
 		// The runtime requires module identifiers to be relative paths
 		const name = path.relative("", identifier);

packages/miniflare/test/index.spec.ts

@@ -233,7 +233,7 @@ test("Miniflare: custom service binding to another Miniflare instance", async (t
 	});
 });
 
-test("Miniflare: uses custom upstream as origin", async (t) => {
+test("Miniflare: custom upstream as origin", async (t) => {
 	const upstream = await useServer(t, (req, res) => {
 		res.end(`upstream: ${new URL(req.url ?? "", "http://upstream")}`);
 	});
@@ -250,3 +250,23 @@ test("Miniflare: uses custom upstream as origin", async (t) => {
 	const res = await mf.dispatchFetch("https://random:0/path?a=1");
 	t.is(await res.text(), "upstream: http://upstream/extra/path?a=1");
 });
+
+test("Miniflare: `node:` and `cloudflare:` modules", async (t) => {
+	const mf = new Miniflare({
+		modules: true,
+		compatibilityFlags: ["nodejs_compat"],
+		script: `
+    import assert from "node:assert";
+    import { Buffer } from "node:buffer";
+    import { connect } from "cloudflare:sockets"; 
+    export default {
+      fetch() {
+        assert.strictEqual(typeof connect, "function");
+        return new Response(Buffer.from("test").toString("base64"))
+      }
+    }
+    `,
+	});
+	const res = await mf.dispatchFetch("http://localhost");
+	t.is(await res.text(), "dGVzdA==");
+});