no-array-push-push and prefer-ternary: Improve same reference detection

[fisker]

Copied a util function isSameReference from ESLint core.

---

no-array-push-push:

foo().push(1);
foo().push(2);

This was invalid, now it's not considered the same array.

foo.bar.push(1);
foo
	.bar.push(1);

Was not considered same array (we used source code to compare), now they can be recognized.

---

prefer-ternary:

Only check Identifier before, same MemberExpression is recognized.

if (test) {
	foo.bar = 1;
} else {
	foo.bar = 2;
}

->

foo.bar = test ? 1 : 2;