s390: [heap] Relocating the write barrier flag on s390

Port ae60ea7e

Original Commit Message:

    The mode without write barriers works only if incremental marking
    is disabled and the single generation mode is enabled.

R=wangrong089@gmail.com, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: If2eb047bed41b92a0366c1401d0acf069257b650
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1733730Reviewed-by: Milad Farazmand <miladfar@ca.ibm.com>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#63080}

src/compiler/backend/s390/instruction-selector-s390.cc

@@ -727,7 +727,8 @@ static void VisitGeneralStore(
   Node* base = node->InputAt(0);
   Node* offset = node->InputAt(1);
   Node* value = node->InputAt(2);
-  if (write_barrier_kind != kNoWriteBarrier) {
+  if (write_barrier_kind != kNoWriteBarrier &&
+      V8_LIKELY(!FLAG_disable_write_barriers)) {
     DCHECK(CanBeTaggedPointer(rep));
     AddressingMode addressing_mode;
     InstructionOperand inputs[3];
@@ -820,9 +821,7 @@ static void VisitGeneralStore(
 
 void InstructionSelector::VisitStore(Node* node) {
   StoreRepresentation store_rep = StoreRepresentationOf(node->op());
-  WriteBarrierKind write_barrier_kind = V8_LIKELY(!FLAG_disable_write_barriers)
-                                            ? store_rep.write_barrier_kind()
-                                            : kNoWriteBarrier;
+  WriteBarrierKind write_barrier_kind = store_rep.write_barrier_kind();
   MachineRepresentation rep = store_rep.representation();
 
   VisitGeneralStore(this, node, rep, write_barrier_kind);