Do not deduplicate code if --debuggable is set.

This ensures that the correct method is displayed in backtrace, and it
makes it possible to reliably set native breakpoints in the methods.

I assume this will also be needed for java debugging as soon as the
ArtMethod* is removed from the stackframe.

Change-Id: I289e85461c231fde2d45473bb19aff9ad5fb496d