[26/n] Internal 4GB allocator.

- change the way we handle blocked commands.
- instead of allocating CPU pointer and populating it with commands, create
real IndirectHeap that may be later submitted to the GPU
- that removes a lot of copy operations that were happening on submit time
- for device enqueue, this requires dsh & shh to be passed directly to the
underlying commands, in that scenario device queue buffers are not used

Change-Id: I1124a8edbb46777ea7f7d3a5946f302e7fdf9665

unit_tests/gen8/scheduler_dispatch_tests.cpp

@@ -55,7 +55,9 @@ BDWTEST_F(BdwSchedulerTest, givenCallToDispatchSchedulerWhenPipeControlWithCSSta
             *pCmdQ,
             *pDevQueueHw,
             pDevice->getPreemptionMode(),
-            scheduler);
+            scheduler,
+            &pCmdQ->getIndirectHeap(IndirectHeap::SURFACE_STATE),
+            pDevQueueHw->getIndirectHeap(IndirectHeap::DYNAMIC_STATE));
 
         HardwareParse hwParser;
         hwParser.parseCommands<FamilyType>(commandStream, 0);