Add runtime support for method based compilation.

Enhanced code cache management to accommodate both trace and method
compilations. Also implemented a hacky dispatch routine for virtual
leaf methods.

Microbenchmark showed 3x speedup in leaf method invocation.

Change-Id: I79d95b7300ba993667b3aa221c1df9c7b0583521
diff --git a/vm/compiler/codegen/Optimizer.h b/vm/compiler/codegen/Optimizer.h
index d42fe87..2b05476 100644
--- a/vm/compiler/codegen/Optimizer.h
+++ b/vm/compiler/codegen/Optimizer.h
@@ -29,6 +29,7 @@
     kTrackLiveTemps,
     kSuppressLoads,
     kMethodInlining,
+    kMethodJit,
 } optControlVector;
 
 /* Forward declarations */