enhanced support for reserving a block of memory on the stack such that the block can be a mix of primitive data and object pointers
added AllocaNode for reserving a block of memory in the stack frame of a method
Ruby: disabled debugging and tracing while they’re broken.
Fix graph mark comparison in TruffleCache

--HG--
extra : rebase_source : c064c851e7da5f4eea615087f97eb0b2c73da92f
refactored ForeignCallStub.GraphBuilder into top level GraphKit class