getExpectedResponseHeadersString = function (expectedResponseHeaders) {
	let expectedResponseHeadersString = "";
	if (expectedResponseHeaders) {
		for (const header of expectedResponseHeaders) {
			if (expectedResponseHeadersString.length === 0) {
				expectedResponseHeadersString = `${header}`;
			} else {
				expectedResponseHeadersString = `${expectedResponseHeadersString},${header}`;
			}
		}
		return expectedResponseHeaders;
	}
	return undefined;
}
Gets the part of the CORS URL that represents the expected HTTP headers to receive.
@param {Array.<string>} expectedResponseHeaders the expected HTTP headers to receive
@returns {string} to be used as the expected HTTP-headers component in CORS URL.