Get a new vinyl-file for the given path, with given options. If already a vinyl-file,just return it.

@param {string|VinylFile} filePath		The path to load from.
@param {Object}options					Options object.
@returns  {VinylFile}					The vinyl-file object.
async function getVinylFile(filePath, options) {
	if (!isString(filePath)) {
		if (!options.lookup.has(filePath.path)) options.lookup.set(filePath.path, filePath);
		return filePath;
	}
	if (options.lookup.has(filePath)) return options.lookup.get(filePath);
	return createVinylFile(filePath, options);
}