Add a prepare for register allocation pass.

- Currently the pass just changes the uses of checks to the
  actual values.
- Also optimize array access, now that inputs can be constants.
- And fix another bug in the register allocator reveiled by
  this change.

Change-Id: I43be0dbde9330ee5c8f9d678de11361292d8bd98
diff --git a/compiler/Android.mk b/compiler/Android.mk
index 133044a..edc5bd0 100644
--- a/compiler/Android.mk
+++ b/compiler/Android.mk
@@ -100,6 +100,7 @@
 	optimizing/nodes.cc \
 	optimizing/optimizing_compiler.cc \
 	optimizing/parallel_move_resolver.cc \
+	optimizing/prepare_for_register_allocation.cc \
 	optimizing/register_allocator.cc \
 	optimizing/ssa_builder.cc \
 	optimizing/ssa_liveness_analysis.cc \