Use StrictModeFlag in preparser and preparse data.

src/preparser.cc

Index: src/preparser.cc
diff --git a/src/preparser.cc b/src/preparser.cc
index 3313658ef72c4fa398c46727407fcd8915374225..b1628eb5c54d5dde11b6dedb1372be5bf54acfce 100644
--- a/src/preparser.cc
+++ b/src/preparser.cc
@@ -1364,7 +1364,7 @@ PreParser::Expression PreParser::ParseFunctionLiteral(bool* ok) {
     log_->LogFunction(function_block_pos, end_pos,
                       function_scope.materialized_literal_count(),
                       function_scope.expected_properties(),
-                      strict_mode() ? 1 : 0);
+                      strict_mode_flag());
   } else {
     ParseSourceElements(i::Token::RBRACE, CHECK_OK);
     Expect(i::Token::RBRACE, CHECK_OK);