Incorrect copyright header in src/jdk.jdwp.agent/share/native/libjdwp/ThreadGroupReferenceImpl.h

The following file has an incorrect header format:
src/jdk.jdwp.agent/share/native/libjdwp/ThreadGroupReferenceImpl.h

  * Copyright (c) 1998, 2020 Oracle and/or its affiliates. All rights reserved.

Missing comma after the second year, YEAR should be "2020,"
%YEARS% should be one of two formats

    "YEAR,"
    "YEAR, YEAR,"

You can verify the header is correct with make/scripts/lic_check.sh to make sure each file now passes.

The template is located at:
  make/templates/gpl-header
  make/templates/gpl-cp-header