8235760: ZGC: Implement precise check for @require vm.gc.Z for Windows

[Per Liden]

Thanks for fixing, looks good!

/Per

On 12/11/19 6:55 PM, Stefan Karlsson wrote:
> Per wanted to move the is_os_supported from ZInitialize to ZArguments.
> 
> Updated webrevs:
>   https://cr.openjdk.java.net/~stefank/8235760/webrev.02.delta/
>   https://cr.openjdk.java.net/~stefank/8235760/webrev.02/
> 
> StefanK
> 
> On 2019-12-11 13:10, Stefan Karlsson wrote:
>> Hi all,
>>
>> Please review this patch to reimplemente @require vm.gc.Z and 
>> WB_IsGCSupported to use a more precise check on Windows.
>>
>> https://cr.openjdk.java.net/~stefank/8235760/webrev.01/
>> https://bugs.openjdk.java.net/browse/JDK-8235760
>>
>> With this patch we call into the VM and try to resolve the required 
>> Windows APIs, instead of doing string comparisons on system properties.
>>
>> Thanks,
>> StefanK
>