deps: fix up v8 after fd80a3

fd80a31e0697d6317ce8c2d289575399f4e06d21 has introduced a segfault
during redundant boundary check elimination (#8208).

The problem consists of two parts:

  1. Abscense of instruction iterator in
     `EliminateRedundantBoundsChecks`. It was present in recent v8, but
     wasn't considered important at the time of backport. However, since
     the function is changing instructions order in block, it is
     important to not rely at `i->next()` at the end of the loop.
  2. Too strict ASSERT in `MoveIndexIfNecessary`. It is essentially a
     backport of a45c96a from v8's upstream. See
     v8@a45c96ab for details.

fix #8208

Signed-off-by: Jeroen Ooms <[email protected]>

src/hydrogen.cc

@@ -3546,7 +3546,11 @@ class BoundsCheckBbData: public ZoneObject {
   void MoveIndexIfNecessary(HValue* index_raw,
                             HBoundsCheck* insert_before,
                             HInstruction* end_of_scan_range) {
-    ASSERT(index_raw->IsAdd() || index_raw->IsSub());
+    if (!index_raw->IsAdd() && !index_raw->IsSub()) {
+      // index_raw can be HAdd(index_base, offset), HSub(index_base, offset),
+      // or index_base directly. In the latter case, no need to move anything.
+      return;
+    }
     HBinaryOperation* index =
         HArithmeticBinaryOperation::cast(index_raw);
     HValue* left_input = index->left();
@@ -3581,7 +3585,6 @@ class BoundsCheckBbData: public ZoneObject {
                     HBoundsCheck* tighter_check) {
     ASSERT(original_check->length() == tighter_check->length());
     MoveIndexIfNecessary(tighter_check->index(), original_check, tighter_check);
-    original_check->ReplaceAllUsesWith(original_check->index());
     original_check->SetOperandAt(0, tighter_check->index());
   }
 };
@@ -3624,7 +3627,9 @@ void HGraph::EliminateRedundantBoundsChecks(HBasicBlock* bb,
                                             BoundsCheckTable* table) {
   BoundsCheckBbData* bb_data_list = NULL;
 
-  for (HInstruction* i = bb->first(); i != NULL; i = i->next()) {
+  HInstruction* next;
+  for (HInstruction* i = bb->first(); i != NULL; i = next) {
+    next = i->next();
     if (!i->IsBoundsCheck()) continue;
 
     HBoundsCheck* check = HBoundsCheck::cast(i);