RFR: JDK-8155632: Remove debuginfo from jmod files

[Erik Joelsson]

The jmod files currently contain debug information and it has been 
concluded that they shouldn't. This patch filters out the debug 
information from the jmod files and adds a new build step in images to 
copy the appropriate set of debuginfo into the images. Note that this 
patch does not aim on changing the way we handle debuginfo in any other 
way. This will be attacked more in depth in JDK-8150009, which in turn 
depends on JDK-8136777.

Bug: https://bugs.openjdk.java.net/browse/JDK-8155632
Webrev: http://cr.openjdk.java.net/~erikj/8155632/webrev.top.01/

/Erik