Fix sandbox restore not handling stubbed functions

[thamion]

Purpose (TL;DR) - mandatory

Sandbox restore is not restoring functions stubbed by stub(func). This PR aligns the behaviour of stuband restore.

Background (Problem in detail) - optional

This is an issue when stubbing, for example, axios instances. Those are build in a way that looses their original object prototype. stub(axios) will work fine and stub all methods as expected, but restore wont work.

Solution - optional

The issue can be fixed by aligning the sandbox code

sinon/lib/sinon/sandbox.js

Lines 410 to 411 in 2605504

	const isSpyingOnEntireObject =
	typeof property === "undefined" && typeof object === "object";

with the stub code

sinon/lib/sinon/stub.js

Lines 91 to 94 in 2605504

	const isObjectOrFunction =
	typeof object === "object" || typeof object === "function";
	const isStubbingEntireObject =
	typeof property === "undefined" && isObjectOrFunction;

How to verify - mandatory

1. Check out this branch
2. npm install
3. npm run test

Checklist for author

• npm run lint passes
• References to standard library functions are cached.

[fatso83]

Ran the sauce labs test locally. Works fine. Thank you!