[Pivots] Support toggleAttribute and attributes

[nolanlawson]

Description

Pivot classes currently handle setAttribute and removeAttribute, but not toggleAttribute or attributes:

lwc/packages/@lwc/engine-dom/src/custom-elements/create-scoped-registry.ts

Lines 296 to 333 in d5bf91e

	defineProperties(instance, {
	setAttribute: {
	value: function setAttribute(name: string, value: any) {
	if (newObservedAttributes.has(name)) {
	const old = nativeGetAttribute.call(this, name);
	nativeSetAttribute.call(this, name, value);
	try {
	attributeChangedCallback!.call(this, name, old, value + '');
	} catch (error) {
	throwAsyncError(error);
	}
	} else {
	nativeSetAttribute.call(this, name, value);
	}
	},
	writable: true,
	enumerable: true,
	configurable: true,
	},
	removeAttribute: {
	value: function removeAttribute(name: string) {
	if (newObservedAttributes.has(name)) {
	const old = nativeGetAttribute.call(this, name);
	nativeRemoveAttribute.call(this, name);
	try {
	attributeChangedCallback!.call(this, name, old, null);
	} catch (error) {
	throwAsyncError(error);
	}
	} else {
	nativeRemoveAttribute.call(this, name);
	}
	},
	writable: true,
	enumerable: true,
	configurable: true,
	},
	});

Related: #2994

[git2gus]

This issue has been linked to a new work item: W-12075447

[nolanlawson]

Pivots were dropped in #3310

[caridy]

@rwaldron do we need this in locker?