test with custom modulePrefix (for Android & iOS)

covers extra breaking mutation 2 FROM PR #83:

diff --git a/lib/normalized-options.js b/lib/normalized-options.js
index 9c49d88..e4576e1 100644
--- a/lib/normalized-options.js
+++ b/lib/normalized-options.js
@@ -10,7 +10,7 @@ module.exports = (options) => {

   const prefix = options.prefix || '';

-  const modulePrefix = options.modulePrefix || DEFAULT_MODULE_PREFIX;
+  const modulePrefix = DEFAULT_MODULE_PREFIX;

   if (typeof name !== 'string') {
     throw new TypeError("Please write your library's name");

Author: Christopher J. Brody