Labels using Block numbers for better cfg file output

[Caspole, Eric]

Hi everybody,
I have been using the c1visualizer with our Graal HSAIL code for about 2 weeks now and it is really nice. I made a small change to the label numbering in Graal to use the Block id as the Label id, so that in the output cfg file the labels in our HSAIL output match the block numbering that appear in the c1visualizer. That way it is easy to glance back and forth between the HSAIL and the CFG in the visualizer and follow along. It worked for a couple different examples/tests that I tried.

 http://cr.openjdk.java.net/~ecaspole/label_block_id.00/webrev/

I only made this change for HSAIL but I find it very helpful. Let me know what you think.
Regards,
Eric