Make suspend checks note have side effects.

Also adjust gtests.

Change-Id: I5e1a3e53115812b45ec7f4b6f50ba468fa7ac6b1
diff --git a/compiler/optimizing/nodes.h b/compiler/optimizing/nodes.h
index faed1ef..944e803 100644
--- a/compiler/optimizing/nodes.h
+++ b/compiler/optimizing/nodes.h
@@ -1796,7 +1796,7 @@
 class HSuspendCheck : public HTemplateInstruction<0> {
  public:
   explicit HSuspendCheck(uint32_t dex_pc)
-      : HTemplateInstruction(SideEffects::ChangesSomething()), dex_pc_(dex_pc) {}
+      : HTemplateInstruction(SideEffects::None()), dex_pc_(dex_pc) {}
 
   virtual bool NeedsEnvironment() const {
     return true;