Make it possible to pass an arena allocator to HLoopOptimization.

loop_optimization_test uses memory from HLoopOptimization's
allocator, which is scoped by the Run method.

Fix is to pass custom allocator.

test: m test-art-host-gtest
Change-Id: I359330e22202519f400a26da5403eeb00f0b2db4
diff --git a/compiler/optimizing/loop_optimization_test.cc b/compiler/optimizing/loop_optimization_test.cc
index 4e007d4..4d54afd 100644
--- a/compiler/optimizing/loop_optimization_test.cc
+++ b/compiler/optimizing/loop_optimization_test.cc
@@ -31,7 +31,7 @@
         allocator_(&pool_),
         graph_(CreateGraph(&allocator_)),
         iva_(new (&allocator_) HInductionVarAnalysis(graph_)),
-        loop_opt_(new (&allocator_) HLoopOptimization(graph_, iva_)) {
+        loop_opt_(new (&allocator_) HLoopOptimization(graph_, iva_, &allocator_)) {
     BuildGraph();
   }