webrev for hsail atomicexch support

[Deneau, Tom]

Earlier this week I was helping Christian by looking into some hsail problems that arose from his AtomicReadAndAdd and AtomicReadAndWrite nodes.  One of the problems turned out to be a bug in the hsail simulator for the hsail atomic_exch instruction which AtomicReadAndWrite nodes would emit.  I have uploaded an okra-1.9-with-sim.jar which has this problem fixed.  And the following webrev for graal specifies the use of okra-1.9.

     http://cr.openjdk.java.net/~tdeneau/graal-webrevs/webrev-hsail-atomicexch-support/webrev

In addition,

*         added support for handling AtomicReadAndWrite node in hsail backend.  I had given these to Christian earlier but we didn't include it when the test that used it, AtomicRefernceGetAndSetTest, still did not pass.

*         Re-enabled the junit test AtomicRefernceGetAndSetTest, it had been turned off when we saw these problems.

*         added a couple of other GetAndSet tests for Int and Long.

*         added comments to @Ignore annotation in a few other tests.

-- Tom