[turbofan] Add initial support for growing stores.

src/compiler/simplified-lowering.cc

Index: src/compiler/simplified-lowering.cc
diff --git a/src/compiler/simplified-lowering.cc b/src/compiler/simplified-lowering.cc
index f5e636546a8bf62efc0f2783c0c69931fc8f5ce7..e91ff0c13b3f32f01dea6595d7a9a09b049b4a0d 100644
--- a/src/compiler/simplified-lowering.cc
+++ b/src/compiler/simplified-lowering.cc
@@ -2385,6 +2385,15 @@ class RepresentationSelector {
       case IrOpcode::kEnsureWritableFastElements:
         return VisitBinop(node, UseInfo::AnyTagged(),
                           MachineRepresentation::kTagged);
+      case IrOpcode::kMaybeGrowFastElements: {
+        ProcessInput(node, 0, UseInfo::AnyTagged());         // object
+        ProcessInput(node, 1, UseInfo::AnyTagged());         // elements
+        ProcessInput(node, 2, UseInfo::TruncatingWord32());  // index
+        ProcessInput(node, 3, UseInfo::TruncatingWord32());  // length
+        ProcessRemainingInputs(node, 4);
+        SetOutput(node, MachineRepresentation::kTagged);
+        return;
+      }
 
       //------------------------------------------------------------------
       // Machine-level operators.