refactored state cleaning in PEA MergeProcessor
fixed canonicalization of ArrayEqualsNode, added Virtualizable implementation
TruffleCompiler: print hint if hitting the assertion

--HG--
extra : rebase_source : 142109da01c3e218322cc8a6f9e43fe76f7e3e41
AbstractNewObjectNode: simplification should not remove a node more than once

--HG--
extra : rebase_source : f9187d90d038f471733249cc455ae302f5ebb730