Don't pre-initialise block contexts with holes

src/compiler/js-typed-lowering.cc

Index: src/compiler/js-typed-lowering.cc
diff --git a/src/compiler/js-typed-lowering.cc b/src/compiler/js-typed-lowering.cc
index a31aa0070c678217d1e4051170d21c7e88f5e217..5e0712a7f1b58bfaab4a677f8dcc6fa5433dcf7f 100644
--- a/src/compiler/js-typed-lowering.cc
+++ b/src/compiler/js-typed-lowering.cc
@@ -2068,7 +2068,7 @@ Reduction JSTypedLowering::ReduceJSCreateBlockContext(Node* node) {
     a.Store(AccessBuilder::ForContextSlot(Context::NATIVE_CONTEXT_INDEX),
             native_context);
     for (int i = Context::MIN_CONTEXT_SLOTS; i < context_length; ++i) {
-      a.Store(AccessBuilder::ForContextSlot(i), jsgraph()->TheHoleConstant());
+      a.Store(AccessBuilder::ForContextSlot(i), jsgraph()->UndefinedConstant());
     }
     RelaxControls(node);
     a.FinishAndChange(node);