Make sure we always temp-zone parse if we preparse toplevel

BUG=

Review-Url: https://codereview.chromium.org/2421493002
Cr-Commit-Position: refs/heads/master@{#40296}

src/parsing/parser.cc

@@ -2643,8 +2643,9 @@ FunctionLiteral* Parser::ParseFunctionLiteral(
   bool use_temp_zone =
       (FLAG_lazy_inner_functions
            ? can_preparse
-           : (allow_lazy() && function_type == FunctionLiteral::kDeclaration &&
-              eager_compile_hint == FunctionLiteral::kShouldLazyCompile)) &&
+           : (is_lazy_top_level_function ||
+              (allow_lazy() && function_type == FunctionLiteral::kDeclaration &&
+               eager_compile_hint == FunctionLiteral::kShouldLazyCompile))) &&
       !(FLAG_validate_asm && scope()->IsAsmModule());
   bool is_lazy_inner_function =
       use_temp_zone && FLAG_lazy_inner_functions && !is_lazy_top_level_function;