RFR: JDK-8202052: Disable warnings when building libawt with VS2017

[Mikael Vidstedt]

Please review the following change which disables some warnings in libawt which show up when building with VS2017:

bug: https://bugs.openjdk.java.net/browse/JDK-8202052 <https://bugs.openjdk.java.net/browse/JDK-8202052>
webrev: http://cr.openjdk.java.net/~mikael/webrevs/8202062/webrev.00/open/webrev/ <http://cr.openjdk.java.net/~mikael/webrevs/8202062/webrev.00/open/webrev/>


Please note that I also filed an issue which covers addressing these warnings in the Right(tm) way (and then removing the disabling of the warnings):

https://bugs.openjdk.java.net/browse/JDK-8202051 <https://bugs.openjdk.java.net/browse/JDK-8202051>


I have tested this with VS2017, and will also verify that it works with the existing toolchain version (used at Oracle).

Cheers,
Mikael