8177530: Module system implementation refresh (4/2017)
Reviewed-by: mchung, alanb
Contributed-by: alan.bateman@oracle.com, mandy.chung@oracle.com

8156147: NPE in InstrumentationImpl.transform when loading classes from -Xbootclasspath/a
Summary: Use the jdk.internal.loader.Bootloader if the loader argument is null
Reviewed-by: alanb