[foreign] RFR 8217380: LayoutType::ofStruct should try to resolve Struct layout

[Jorn Vernee]

Hi,

Please review the following patch.

Bug: https://bugs.openjdk.java.net/browse/JDK-8217380
Webrev: 
http://cr.openjdk.java.net/~jvernee/panama/webrevs/8217380/webrev.00/

Thanks,
Jorn