feat(web): add isSameNode for duplicate quotient-node detection 🚂

[jahorton]

Continuing from #15508, this defines a method useful for determining if one SearchQuotientNode is a 100% match and duplicate for another node. While .isSameNode is only leveraged in unit tests within this PR, it sees use in runtime code starting with #15031.

Build-bot: skip build:web
Test-bot: skip

[keymanapp-test-bot]

User Test Results

Test specification and instructions

User tests are not required

Test Artifacts

• Web
  • KeymanWeb Test Home - build : all tests passed (no artifacts on BuildLevel "build")

[darcywong00]

Do these not have parents to check for match?

[jahorton]

It's the 'root' node - there is no parent here.

[darcywong00]

lgtm

[ermshiperete]

LGTM

[ermshiperete]

Suggested change

	// Easiest cases: when the instances or their ' `spaceId` matches, we have
	// Easiest cases: when the instances or their `spaceId` matches, we have

[ermshiperete]

Do we have to check that this and space have the same number of parents?

Suggested change

	// We need to check if the parents match. Done naively in the manner below, this is O(N^2).
	// Granted, we shouldn't have _that_ many incoming paths.
	if(this.parents.find((path) => !space.parents.find((path2) => path.isSameNode(path2)))) {
	return false;
	}
	if(this.parents.length != space.parents.length) {
	return false;
	}
	// We need to check if the parents match. Done naively in the manner below, this is O(N^2).
	// Granted, we shouldn't have _that_ many incoming paths.
	if(this.parents.find((path) => !space.parents.find((path2) => path.isSameNode(path2)))) {
	return false;
	}