[turbofan] Ensure stackcheck flags do something.

While the intention is to eventually do away with
FLAG_turbo_loop_stackcheck and FLAG_turbo_preprocess_range,
they are useful for the interim we are still testing and
benchmarking the feature.

Review URL: https://codereview.chromium.org/1314163003

Cr-Commit-Position: refs/heads/master@{#30399}

src/compiler/ast-graph-builder.cc

@@ -2932,7 +2932,7 @@ void AstGraphBuilder::VisitInScope(Statement* stmt, Scope* s, Node* context) {
 void AstGraphBuilder::VisitIterationBody(IterationStatement* stmt,
                                          LoopBuilder* loop) {
   ControlScopeForIteration scope(this, stmt, loop);
-  if (FLAG_turbo_loop_stackcheck) {
+  if (FLAG_turbo_loop_stackcheck || !info()->shared_info()->asm_function()) {
     Node* node = NewNode(javascript()->StackCheck());
     PrepareFrameState(node, stmt->StackCheckId());
   }

src/compiler/pipeline.cc

@@ -1360,13 +1360,17 @@ void Pipeline::AllocateRegisters(const RegisterConfiguration* config,
     CHECK(!data->register_allocation_data()->ExistsUseWithoutDefinition());
   }
 
-  Run<SplinterLiveRangesPhase>();
+  if (FLAG_turbo_preprocess_ranges) {
+    Run<SplinterLiveRangesPhase>();
+  }
 
   // TODO(mtrofin): re-enable greedy once we have bots for range preprocessing.
   Run<AllocateGeneralRegistersPhase<LinearScanAllocator>>();
   Run<AllocateDoubleRegistersPhase<LinearScanAllocator>>();
 
-  Run<MergeSplintersPhase>();
+  if (FLAG_turbo_preprocess_ranges) {
+    Run<MergeSplintersPhase>();
+  }
 
   if (FLAG_turbo_frame_elision) {
     Run<LocateSpillSlotsPhase>();