Optimize suspend checks in optimizing compiler.

- Remove the ones added during graph build (they were added
  for the baseline code generator).
- Emit them at loop back edges after phi moves, so that the test
  can directly jump to the loop header.
- Fix x86 and x86_64 suspend check by using cmpw instead of cmpl.

Change-Id: I6fad5795a55705d86c9e1cb85bf5d63dadfafa2a
diff --git a/compiler/optimizing/optimizing_compiler.cc b/compiler/optimizing/optimizing_compiler.cc
index 702eba1..65bdb18 100644
--- a/compiler/optimizing/optimizing_compiler.cc
+++ b/compiler/optimizing/optimizing_compiler.cc
@@ -26,6 +26,7 @@
 #include "driver/dex_compilation_unit.h"
 #include "graph_visualizer.h"
 #include "gvn.h"
+#include "instruction_simplifier.h"
 #include "nodes.h"
 #include "register_allocator.h"
 #include "ssa_phi_elimination.h"
@@ -261,6 +262,7 @@
 
     SsaRedundantPhiElimination(graph).Run();
     SsaDeadPhiElimination(graph).Run();
+    InstructionSimplifier(graph).Run();
     GlobalValueNumberer(graph->GetArena(), graph).Run();
     visualizer.DumpGraph(kGVNPassName);