more robust handling of errors in Constant.toString()
MacroNode: do not modify the cached version of the graph
Add locally specified guards to substitutions
Use compile ids assigned by hotspot
Add probabilities to NewObjectSnippets.allocateInstanceDynamic

--HG--
extra : rebase_source : fbe0dafefd4873d4567b19fdb51bd11c0331686c
Remove createNullCheckGuard from LoweringTool. Use generic createGuard instead

--HG--
extra : rebase_source : ad546a609194dd29726f5f1b0e291d45d4be70f8
Removing usage of NullCheckNode in GuardNode.lowerGuard()

--HG--
extra : rebase_source : b98f24ef6b8440511ed1f651a4e565c052cd22e7
remove check for null in recordImplicitException, it should not be called with a null LIRFrameState

--HG--
extra : rebase_source : 4efb24d74d1cf53097c098d63923fb8259226937
Make a separate phase to use trapping null checks instead of branches when implicitNullCheckLimit > 0

--HG--
extra : rebase_source : be783e0c23986190756a2d329fe4b89390c60017
Adjust expected test result in WriteBarrierVerificationTest

--HG--
extra : rebase_source : 11547359728c742e5f839255e0f62cff7f912ac1
added mechanism for a (GPU) backend to override/supply the initial graph in the compilation pipeline
PTX backend can alter compilation pipeline to offload selected code to the GPU