Turn the unresolved-references list into a linked list using the VariableProxies themselves

src/ast/ast.cc

Index: src/ast/ast.cc
diff --git a/src/ast/ast.cc b/src/ast/ast.cc
index 1554a5e0b9761856b86ba99263743dc96c6627db..e8f7c4c24589f436f92aa9cecadf67d489a0668e 100644
--- a/src/ast/ast.cc
+++ b/src/ast/ast.cc
@@ -178,7 +178,8 @@ VariableProxy::VariableProxy(Zone* zone, Variable* var, int start_position,
                  IsAssignedField::encode(false) |
                  IsResolvedField::encode(false)),
       end_position_(end_position),
-      raw_name_(var->raw_name()) {
+      raw_name_(var->raw_name()),
+      next_unresolved_(nullptr) {
   BindTo(var);
 }
 
@@ -190,7 +191,8 @@ VariableProxy::VariableProxy(Zone* zone, const AstRawString* name,
                  IsAssignedField::encode(false) |
                  IsResolvedField::encode(false)),
       end_position_(end_position),
-      raw_name_(name) {}
+      raw_name_(name),
+      next_unresolved_(nullptr) {}
 
 void VariableProxy::BindTo(Variable* var) {
   DCHECK((is_this() && var->is_this()) || raw_name() == var->raw_name());