RFR 8158507: JShell: new jdk.jshell.MemoryFileManager(StandardJavaFileManager, JShell) creates a jdk.jshell.MemoryFileManager$REPLClassLoader classloader, which should be performed within a doPrivileged block

[Robert Field]

The solution for this one is to simply remove code that was left around 
to support potential restoration of process-local execution support.  
Process-local execution is now directly supported through the SPI and 
using jdk.jshell.execution.LocalExecutionControl.

Please review...

Bug:
     https://bugs.openjdk.java.net/browse/JDK-8158507

Webrev:
    http://cr.openjdk.java.net/~rfield/8158507v0.webrev/

Thanks,
Robert