RFR: 8324799: Use correct extension for C++ test headers [v2]

[Kim Barrett]

On Wed, 28 Feb 2024 14:11:49 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> test/hotspot/jtreg/serviceability/jvmti/events/SingleStep/singlestep01/libsinglestep01.cpp line 28:
>> 
>>> 26: #include <string.h>
>>> 27: #include <jvmti.h>
>>> 28: #include "jvmti_common.hpp"
>> 
>> The copyright of this file is wrong.
>> 
>>>  * Copyright (c) 200
>>>  * git 3, 2022, Oracle and/or its affiliates. All rights reserved.
>>>  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
>
> It's weird that our jcheck tools didn't find the broken copyright.

I thought it was odd too, so started a discussion on an internal slack channel about copyright checking.
It turns out there are a number that need some work.  I'm fixing this one, removing the newline and "git "
and updating the second year.  The starting year of 2003 seems odd, since this file seems to be fairly
new (from Virtual Threads), but 2003 is also what's in the adjacent .java file.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18035#discussion_r1506813867