public static String getTrustStorePassword() {
        String password = System.getProperty("javax.net.ssl.trustStorePassword");
        return password == null ? getKeystorePassword() : password;
    }
Return JVM param set truststore password or keystore password if not set.
If still not set, will return default password

@return truststore password as string
src/test/java/spark/util/SparkTestUtil.java