[Parser] Don't internalize on-the-fly.

test/cctest/asmjs/test-asm-typer.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <cstring>
 #include <functional>
 #include <iostream>
 #include <memory>
 
 #include "src/asmjs/asm-typer.h"
@@ skipping 258 matching lines @@
                 << typer_->error_message() << "'\n";
       return false;
     }
 
     return true;
   }
 
  private:
   Variable* DeclareVariable(VariableName var_name) {
     auto* name_ast_string = ast_value_factory_.GetOneByteString(var_name.name_);
+    ast_value_factory_.Internalize(isolate_);
     return var_name.mode_ == DYNAMIC_GLOBAL
                ? outer_scope_->DeclareDynamicGlobal(name_ast_string,
                                                     Variable::NORMAL)
                : module_->scope()->DeclareLocal(name_ast_string, VAR,
                                                 kCreatedInitialized,
                                                 Variable::NORMAL);
   }
 
   bool ValidateAllStatements(FunctionDeclaration* fun_decl) {
     AsmTyper::FlattenedStatements iter(zone_, fun_decl->fun()->body());
@@ skipping 1705 matching lines @@
   for (size_t ii = 0; ii < arraysize(kTests); ++ii) {
     if (!ValidationOf(Module(kTests[ii]))
              ->FailsWithMessage("Can't assign to immutable symbol")) {
       std::cerr << "Test:\n" << kTests[ii];
       CHECK(false);
     }
   }
 }
 
 }  // namespace