[ignition] Eliminate hole checks where statically possible for loads and stores

src/ast/ast.h

Index: src/ast/ast.h
diff --git a/src/ast/ast.h b/src/ast/ast.h
index 4e0a6a27755c8130d7b4f7da0939c488a866b291..75c548806b792c1ee5e3f55811bd2ea01f663190 100644
--- a/src/ast/ast.h
+++ b/src/ast/ast.h
@@ -1671,6 +1671,13 @@ class VariableProxy final : public Expression {
     bit_field_ = IsNewTargetField::update(bit_field_, true);
   }
 
+  bool needs_hole_check() const {
+    return NeedsHoleCheckField::decode(bit_field_);
+  }
+  void set_needs_hole_check() {
+    bit_field_ = NeedsHoleCheckField::update(bit_field_, true);
+  }
+
   int end_position() const { return end_position_; }
 
   // Bind this proxy to the variable var.
@@ -1706,6 +1713,8 @@ class VariableProxy final : public Expression {
   class IsAssignedField : public BitField<bool, IsThisField::kNext, 1> {};
   class IsResolvedField : public BitField<bool, IsAssignedField::kNext, 1> {};
   class IsNewTargetField : public BitField<bool, IsResolvedField::kNext, 1> {};
+  class NeedsHoleCheckField
+      : public BitField<bool, IsNewTargetField::kNext, 1> {};
 
   // Position is stored in the AstNode superclass, but VariableProxy needs to
   // know its end position too (for error messages). It cannot be inferred from