Simplify PreParser::ParsePrimaryExpression

* src/preparser.cc (PreParser::ParsePrimaryExpression): No need to check
  keywords for validity as identifiers, as ParseIdentifier (called in
  the fallthrough) will take care of it.

Covered by existing tests.

BUG=

Review URL: https://codereview.chromium.org/12600004
Patch from Andy Wingo <wingo@igalia.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13899 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/preparser.cc

@@ -1110,24 +1110,8 @@ PreParser::Expression PreParser::ParsePrimaryExpression(bool* ok) {
       break;
     }
 
-    case i::Token::FUTURE_RESERVED_WORD: {
-      Next();
-      i::Scanner::Location location = scanner_->location();
-      ReportMessageAt(location.beg_pos, location.end_pos,
-                      "reserved_word", NULL);
-      *ok = false;
-      return Expression::Default();
-    }
-
+    case i::Token::FUTURE_RESERVED_WORD:
     case i::Token::FUTURE_STRICT_RESERVED_WORD:
-      if (!is_classic_mode()) {
-        Next();
-        i::Scanner::Location location = scanner_->location();
-        ReportMessageAt(location, "strict_reserved_word", NULL);
-        *ok = false;
-        return Expression::Default();
-      }
-      // FALLTHROUGH
     case i::Token::IDENTIFIER: {
       Identifier id = ParseIdentifier(CHECK_OK);
       result = Expression::FromIdentifier(id);