To my pleasant surprise, the optimized build worked exactly as expected. Here is what I did...
First, I found an existing 'HelloPhoneGap' project for Android. (You can create one from scratch using the instructions at Getting Started for your favorite mobile platform.) The entry point for your app in a PhoneGap build environment is an index.html file within an assets/www directory. For example:
I modified the contents of index.html to point to the buildtest.html file created previously...
<body bgcolor="yellow" >
<li><a href="buildtest.html">optimized dojo build</a>
I copied the three files and directories created from the optimized build into the PhoneGap directory:
Then I compiled, installed, and started the app. It worked out of the box.
When I started the app, the index.html file appeared.
I clicked the link to jump to the optimized dojo build page, buildtest.html. The alert popped up:
After clicking 'OK', I got the version information.