ART: Dead block removal

Adds a new pass which finds all unreachable blocks, typically due to
simplifying an if-condition to a constant, and removes them from the
graph. The patch also slightly generalizes the graph-transforming
operations.

Change-Id: Iff7c97f1d10b52886f3cd7401689ebe1bfdbf456
diff --git a/compiler/optimizing/optimization.cc b/compiler/optimizing/optimization.cc
index b13e07e..c46a219 100644
--- a/compiler/optimizing/optimization.cc
+++ b/compiler/optimizing/optimization.cc
@@ -21,9 +21,9 @@
 
 namespace art {
 
-void HOptimization::MaybeRecordStat(MethodCompilationStat compilation_stat) const {
+void HOptimization::MaybeRecordStat(MethodCompilationStat compilation_stat, size_t count) const {
   if (stats_ != nullptr) {
-    stats_->RecordStat(compilation_stat);
+    stats_->RecordStat(compilation_stat, count);
   }
 }