[foreign] RFR: Windows support

[Sundararajan Athijegannathan]

In response to this email -> 
https://mail.openjdk.java.net/pipermail/panama-dev/2019-January/003680.html

This email is to address webrev for bug 
https://bugs.openjdk.java.net/browse/JDK-8211060

I tested the default native library changes on Mac and Linux. All tests 
run tine. We already discussed about Windows limitation (of having to 
search the entire process for the given symbol because there is no 
equivalent of RTLD_DEFAULT). We may want to leave an explicit comment in 
-> src/java.base/windows/native/libjava/jni_util_md.c.

Looks good for push.

-Sundar