[builtins - Object] Object.getPrototypeOf returning incorrectly

[croraf]

To Reproduce

const c = function a (){};
const d = new c();

Object.getPrototypeOf(d)

Expected behavior
Should return the prototype object whose constructor field points to function a(){}.

undefined is returned instead.

[croraf]

Seems that this is caused by the fact that the following gives undefined:

const c = function a (){};
const d = new c();

d.__proto__;

Checking the code it seems that d.__proto__ during construction is set to c.prototype. And c.prototype outputs this object:

{
  __proto__: {
    constructor: {
      setPrototypeOf: {
        length: 2
      },
      prototype: [Cycle],
        name: Object,
          length: 1,
            defineProperty: {
        length: 3
      },
      getPrototypeOf: {
        length: 1
      },
      is: {
        length: 2
      },
      __proto__: {
        constructor: {
          name: Function,
            prototype: [Cycle],
              length: 1,
                __proto__: undefined
        },
        __proto__: undefined
      }
    },
    hasOwnProperty: {
      length: 0
    },
    propertyIsEnumerable: {
      length: 0
    },
    toString: {
      length: 0
    }
  }
}

EDIT: c.prototype seems to be wrong. It only has the __proto__ property, but it should also have the constructor property pointing to the function a.