Fix test

packages/babel-plugin-proposal-decorators/test/fixtures/2021-12-misc--to-es2015/initProto-existing-derived-constructor/input.js

@@ -0,0 +1,10 @@
+class A extends B {
+  constructor() {
+    let a = 2;
+    super(a);
+    foo();
+  }
+
+  @deco
+  method() {}
+}

packages/babel-plugin-proposal-decorators/test/fixtures/2021-12-misc--to-es2015/initProto-existing-derived-constructor/output.js

@@ -0,0 +1,18 @@
+var _initProto;
+
+class A extends B {
+  constructor() {
+    let a = 2;
+
+    _initProto(super(a));
+
+    foo();
+  }
+
+  method() {}
+
+}
+
+(() => {
+  [_initProto] = babelHelpers.applyDecs(A, [[deco, 2, "method"]], []);
+})();