RFR: JDK-8218055: Use ToolProvider instead of AppRuntimeImageBuilder.

[Andy Herrick]

Please review the jpackage fix for bug [1] at [2].

This is a fix for the JDK-8200758-branch branch of the open sandbox 
repository (jpackage).

This enhancement removes the use of 
jdk.tools.jlink.internal.packager.AppRuntimeImageBuilder in favor of 
invoking jlink directly thru the ToolProvider interface, with associated 
code cleanup.

[1] https://bugs.openjdk.java.net/browse/JDK-8218055

[2] http://cr.openjdk.java.net/~herrick/8218055/webrev.02

/Andy