Add a compilation tracing mechanism to the new compiler.

Code mostly imported from: https://android-review.googlesource.com/#/c/81653/.

Change-Id: I150fe942be0fb270e03fabb19032180f7a065d13
diff --git a/compiler/optimizing/ssa_test.cc b/compiler/optimizing/ssa_test.cc
index 9be2197..415d146 100644
--- a/compiler/optimizing/ssa_test.cc
+++ b/compiler/optimizing/ssa_test.cc
@@ -66,10 +66,10 @@
   int id = 0;
   for (size_t i = 0, e = graph->GetBlocks().Size(); i < e; ++i) {
     HBasicBlock* block = graph->GetBlocks().Get(i);
-    for (HInstructionIterator it(*block->GetPhis()); !it.Done(); it.Advance()) {
+    for (HInstructionIterator it(block->GetPhis()); !it.Done(); it.Advance()) {
       it.Current()->SetId(id++);
     }
-    for (HInstructionIterator it(*block->GetInstructions()); !it.Done(); it.Advance()) {
+    for (HInstructionIterator it(block->GetInstructions()); !it.Done(); it.Advance()) {
       it.Current()->SetId(id++);
     }
   }