Class initialization check elimination.

Also, move null check elimination temporaries to the
ScopedArenaAllocator and reuse the same variables in the
class initialization check elimination.

Change-Id: Ic746f95427065506fa6016d4931e4cb8b34937af
diff --git a/compiler/dex/frontend.cc b/compiler/dex/frontend.cc
index 83fbca5..4485b15 100644
--- a/compiler/dex/frontend.cc
+++ b/compiler/dex/frontend.cc
@@ -44,6 +44,7 @@
   // (1 << kLoadHoisting) |
   // (1 << kSuppressLoads) |
   // (1 << kNullCheckElimination) |
+  // (1 << kClassInitCheckElimination) |
   // (1 << kPromoteRegs) |
   // (1 << kTrackLiveTemps) |
   // (1 << kSafeOptimizations) |