RFR (XS): 8231600: Avoid GCC 8 strncpy error in jdk.jdwp.agent

[Florian Weimer]

* Chris Plummer:

> Fix looks good.

Thanks.  Would you be able to sponsor this change for me?

Florian

> On 9/28/19 2:09 AM, Florian Weimer wrote:
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8231600
>> Webrev: http://cr.openjdk.java.net/~fweimer/8231600/webrev.01/
>>
>> We know the size of the string, so we can use memcpy instead of strncpy.
>>
>> Thanks,
>> Florian