Make special RPO computation iterative during scheduling.

test/unittests/compiler/register-allocator-unittest.cc

Index: test/unittests/compiler/register-allocator-unittest.cc
diff --git a/test/unittests/compiler/register-allocator-unittest.cc b/test/unittests/compiler/register-allocator-unittest.cc
index 752999fc5792d4f08ecd49c43b919455cf049ff8..1c7aeee4fd35dff2bf9f158c7744ceba5b639564 100644
--- a/test/unittests/compiler/register-allocator-unittest.cc
+++ b/test/unittests/compiler/register-allocator-unittest.cc
@@ -97,7 +97,7 @@ class RegisterAllocatorTest : public TestWithZone {
     if (loop_header.IsValid()) {
       basic_block->set_loop_depth(1);
       basic_block->set_loop_header(basic_blocks_[loop_header.ToSize()]);
-      basic_block->set_loop_end(loop_end.ToInt());
+      basic_block->set_loop_end(basic_blocks_[loop_end.ToSize()]);
     }
     InstructionBlock* instruction_block =
         new (zone()) InstructionBlock(zone(), basic_block);