webrev to remove AMD GPU check

[Caspole, Eric]

Hi everybody,
After discussing it with Bharadwaj the other day, I made a webrev to remove AMD GPU detection since for the time being we are only running on the HSAIL simulator, which only depends on shared libraries. I found that since AMD CPUs and GPUs have the same vendor ID, this part was not working as intended if you have a system with an AMD CPU with Nvidia GPU so nothing would be offloaded. We will adjust this AMD APU detection when the real HSA system is generally available.

 http://cr.openjdk.java.net/~ecaspole/no_amd_hw_check/

In the course of this change, I moved the gpu::init during the JVM boot up after the arguments are processed so the +UseHSAILSimulator I added earlier will work correctly.
Let me know what you think,
Thanks,
Eric