RFR: Rename vm_operations_shenandoah.* to shenandoahVMOperations.*

[Roman Kennke]

Upstream renamed vm_operations_$GC.* to $GCVMOperations.*, let's do the
same for Shenandoah:

http://cr.openjdk.java.net/~rkennke/rename-vmops/webrev.00/

Testing: hotspot_gc_shenandoah

Ok?
Roman