Revert "Introduce a class to implement optimization passes."

This reverts commit bf9cd7ba2118a75f5aa9b56241c4d5fa00dedeb8.

Change-Id: I0a483446666c9c24c45925a5fc199debdefd8b3e
diff --git a/compiler/Android.mk b/compiler/Android.mk
index ed07650..13c5671 100644
--- a/compiler/Android.mk
+++ b/compiler/Android.mk
@@ -90,7 +90,7 @@
 	optimizing/code_generator_arm.cc \
 	optimizing/code_generator_x86.cc \
 	optimizing/code_generator_x86_64.cc \
-	optimizing/constant_folding.cc \
+	optimizing/constant_propagation.cc \
 	optimizing/dead_code_elimination.cc \
 	optimizing/graph_checker.cc \
 	optimizing/graph_visualizer.cc \
@@ -98,7 +98,6 @@
 	optimizing/instruction_simplifier.cc \
 	optimizing/locations.cc \
 	optimizing/nodes.cc \
-	optimizing/optimization.cc \
 	optimizing/optimizing_compiler.cc \
 	optimizing/parallel_move_resolver.cc \
 	optimizing/register_allocator.cc \