[es8] Remove syntactic tail calls support.

src/parsing/preparser.cc

 // Copyright 2011 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 <cmath>
 
 #include "src/allocation.h"
 #include "src/base/logging.h"
 #include "src/conversions-inl.h"
 #include "src/conversions.h"
@@ skipping 286 matching lines @@
   BlockState block_state(&scope_state_);
   scope()->SetLanguageMode(
       static_cast<LanguageMode>(class_language_mode | STRICT));
   // TODO(marja): Make PreParser use scope names too.
   // this->scope()->SetScopeName(name);
 
   bool has_extends = Check(Token::EXTENDS);
   if (has_extends) {
     ExpressionClassifier extends_classifier(this);
     ParseLeftHandSideExpression(CHECK_OK);
-    CheckNoTailCallExpressions(CHECK_OK);
     ValidateExpression(CHECK_OK);
     impl()->AccumulateFormalParameterContainmentErrors();
   }
 
   ClassLiteralChecker checker(this);
   bool has_seen_constructor = false;
 
   Expect(Token::LBRACE, CHECK_OK);
   while (peek() != Token::RBRACE) {
     if (Check(Token::SEMICOLON)) continue;
@@ skipping 21 matching lines @@
 
   body->Add(PreParserStatement::ExpressionStatement(return_value), zone());
 }
 
 #undef CHECK_OK
 #undef CHECK_OK_CUSTOM
 
 
 }  // namespace internal
 }  // namespace v8