Vendor dependencies

Let's see how I like this workflow.

vendor/js-sys/tests/wasm/Generator.js

@@ -0,0 +1,23 @@
+exports.one_two_generator = function() {
+  function* generator() {
+    yield 1;
+    yield 2;
+  }
+  return generator();
+};
+
+exports.dummy_generator = function() {
+  function* generator() {
+    const reply = yield '2 * 2';
+    return reply === 4;
+  }
+  return generator();
+};
+
+exports.broken_generator = function() {
+  function* brokenGenerator() {
+    throw new Error('Something went wrong');
+    yield 1;
+  }
+  return brokenGenerator();
+};