ART: Print and dump functionalities per pass

LOG is a great logging tool but sometimes a pass has some debugging text it
 want to be able to turn on/off easily.

By going via a print_pass flag, we can actually turn it on/off easily per pass
 when debugging/instrumenting.

- Added a pass printer to help debug messages for future passes.
- Added a print_pass flag in CompilationUnit to filter out messages.

At the same time, did a similar system for dumping the CFG.

- Also moved some API into public from protected.

Change-Id: Ie0e89a8fc773e8583f3e4ffd6e4bd2eebdbb2bf4
Signed-off-by: Jean Christophe Beyler <jean.christophe.beyler@intel.com>
Signed-off-by: Razvan A Lupusoru <razvan.a.lupusoru@intel.com>
Signed-off-by: Yixin Shou <yixin.shou@intel.com>
Signed-off-by: Chao-ying Fu <chao-ying.fu@intel.com>
Signed-off-by: Udayan Banerji <udayan.banerji@intel.com>