Add test for _initProto with existing constructor

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

@@ -0,0 +1,12 @@
+class A extends B {
+  constructor() {
+    if (Math.random() > 0.5) {
+      super(true);
+    } else {
+      super(false);
+    }
+  }
+
+  @deco
+  method() {}
+}

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

@@ -0,0 +1,20 @@
+var _initProto;
+
+class A extends B {
+  static {
+    [_initProto] = babelHelpers.applyDecs(this, [[deco, 2, "method"]], []);
+  }
+
+  constructor() {
+    var _super;
+
+    if (Math.random() > 0.5) {
+      _super = super(true), _initProto(this), _super;
+    } else {
+      super(false);
+    }
+  }
+
+  method() {}
+
+}

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

@@ -0,0 +1,16 @@
+var _initProto, _super;
+
+class A extends B {
+  static {
+    [_initProto] = babelHelpers.applyDecs(this, [[deco, 2, "method"]], []);
+  }
+
+  constructor() {
+    let a = 2;
+    _super = super(a), _initProto(this), _super;
+    foo();
+  }
+
+  method() {}
+
+}