RFR: 8216154: C4819 warnings at HotSpot sources on Windows

[Kim Barrett]

> On Jan 4, 2019, at 8:33 PM, Yasumasa Suenaga <yasuenag at gmail.com> wrote:
> 
> Hi all,
> 
> Please review this change:
> 
>  JBS: https://bugs.openjdk.java.net/browse/JDK-8216154
>  webrev: http://cr.openjdk.java.net/~ysuenaga/JDK-8216154/webrev.00/
>  Discussion on build-dev: https://mail.openjdk.java.net/pipermail/build-dev/2019-January/024581.html

The preferred idiom to disable a warning over some scope is to use

#pragma warning(push)
#pragma warning(disable : 4819)
…
#pragma warning(pop)