Remove H[Reverse]PostOrderIterator and HInsertionOrderIterator.

Use range-based loops instead, introducing helper functions
ReverseRange() for iteration in reverse order in containers.
When the contents of the underlying container change inside
the loop, use an index-based loop that better exposes the
container data modifications, compared to the old iterator
interface that's hiding it which may lead to subtle bugs.

Test: m test-art-host
Change-Id: I2a4e6c508b854c37a697fc4b1e8423a8c92c5ea0
diff --git a/compiler/optimizing/gvn.cc b/compiler/optimizing/gvn.cc
index 1e86b75..f5931a2 100644
--- a/compiler/optimizing/gvn.cc
+++ b/compiler/optimizing/gvn.cc
@@ -411,8 +411,8 @@
 
   // Use the reverse post order to ensure the non back-edge predecessors of a block are
   // visited before the block itself.
-  for (HReversePostOrderIterator it(*graph_); !it.Done(); it.Advance()) {
-    VisitBasicBlock(it.Current());
+  for (HBasicBlock* block : graph_->GetReversePostOrder()) {
+    VisitBasicBlock(block);
   }
 }