Create a typedef for HInstruction::GetInputs() return type.

And some other cleanup after
    https://android-review.googlesource.com/230742

Test: No new tests. ART test suite passed (tested on host).
Change-Id: I4743bf17544d0234c6ccb46dd0c1b9aae5c93e17
diff --git a/compiler/optimizing/induction_var_analysis.cc b/compiler/optimizing/induction_var_analysis.cc
index 52426d7..129c2a9 100644
--- a/compiler/optimizing/induction_var_analysis.cc
+++ b/compiler/optimizing/induction_var_analysis.cc
@@ -341,7 +341,7 @@
                                                                          HInstruction* phi,
                                                                          size_t input_index) {
   // Match all phi inputs from input_index onwards exactly.
-  auto&& inputs = phi->GetInputs();
+  HInputsRef inputs = phi->GetInputs();
   DCHECK_LT(input_index, inputs.size());
   InductionInfo* a = LookupInfo(loop, inputs[input_index]);
   for (size_t i = input_index + 1; i < inputs.size(); i++) {
@@ -464,7 +464,7 @@
 HInductionVarAnalysis::InductionInfo* HInductionVarAnalysis::SolvePhi(HInstruction* phi,
                                                                       size_t input_index) {
   // Match all phi inputs from input_index onwards exactly.
-  auto&& inputs = phi->GetInputs();
+  HInputsRef inputs = phi->GetInputs();
   DCHECK_LT(input_index, inputs.size());
   auto ita = cycle_.find(inputs[input_index]);
   if (ita != cycle_.end()) {