A64: Prevent repeated restoring of root in gap resolver

BUG=
R=ulan@chromium.org

Review URL: https://codereview.chromium.org/164353002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19368 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/a64/lithium-gap-resolver-a64.cc

@@ -81,6 +81,7 @@ void LGapResolver::Resolve(LParallelMove* parallel_move) {
   if (need_to_restore_root_) {
     ASSERT(kSavedValue.Is(root));
     __ InitializeRootRegister();
+    need_to_restore_root_ = false;
   }
 
   moves_.Rewind(0);