[parser] Only throw spread class property error if it's the first error

Bug: chromium:899474, v8:8363, v8:7926
Change-Id: I89680d35ab2557f5a2b2282813362f5f654862a9
Reviewed-on: https://chromium-review.googlesource.com/c/1304314
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57058}

src/parsing/parser-base.h

@@ -2306,6 +2306,7 @@ ParserBase<Impl>::ParseClassPropertyDefinition(
       return result;
     }
     case ParsePropertyKind::kSpread:
+      RETURN_IF_PARSE_ERROR_CUSTOM(NullLiteralProperty);
       ReportUnexpectedTokenAt(
           Scanner::Location(name_token_position, name_expression->position()),
           name_token);

test/mjsunit/regress/regress-899474.js

+// Copyright 2018 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.
+
+assertThrows("class A {...", SyntaxError);