Do not eliminate bounds checks for "<const> - x".

src/hydrogen-bce.cc

Index: src/hydrogen-bce.cc
diff --git a/src/hydrogen-bce.cc b/src/hydrogen-bce.cc
index c72a8c55d865f7bfdf4c7e21c675a710fd3b9ddd..5b134290ee7a08e9342e206d3425a7b94574974c 100644
--- a/src/hydrogen-bce.cc
+++ b/src/hydrogen-bce.cc
@@ -47,10 +47,7 @@ class BoundsCheckKey : public ZoneObject {
     } else if (check->index()->IsSub()) {
       HSub* index = HSub::cast(check->index());
       is_sub = true;
-      if (index->left()->IsConstant()) {
-        constant = HConstant::cast(index->left());
-        index_base = index->right();
-      } else if (index->right()->IsConstant()) {
+      if (index->right()->IsConstant()) {
         constant = HConstant::cast(index->right());
         index_base = index->left();
       }