RFR (XS) 8237806: Convert TIMEOUT of sun.net.dns.ResolverConfigurationImpl into property

[Denghui Dong]

Hi team,
Could I have a review of a small change that converts TIMEOUT of ResolverConfigurationImpl into property.
Summary:
The value of TIMEOUT of ResolverConfigurationImpl was hardcoded, it's useful to use a system property to specify
the value of it.


JIRA: https://bugs.openjdk.java.net/browse/JDK-8237806
Webrev: http://cr.openjdk.java.net/~ddong/8237806/webrev.00/

Thanks
Denghui Dong