Add more async context tests

packages/babel-core/test/fixtures/transformation/misc/regression-7064/exec.js

@@ -0,0 +1,23 @@
+class Bar {
+  test() {
+    // pass
+    (() => {
+      assert.strictEqual(this.constructor, Bar);
+    })();
+
+    // pass
+    (() => {
+      assert.strictEqual(this.constructor, Bar);
+    }).call(this);
+
+    (async () => {
+      assert.strictEqual(this.constructor, Bar);
+    })();
+
+    (async () => {
+      assert.strictEqual(this.constructor, Bar);
+    }).call(this);
+  }
+}
+
+(new Bar()).test();

packages/babel-core/test/fixtures/transformation/misc/regression-7064/options.json

@@ -0,0 +1,4 @@
+{
+  "plugins": ["transform-async-to-generator"],
+  "presets": ["es2015"]
+}