RFR(M) 8209961: [AOT] crash in Graal stub when -XX:+VerifyOops is used

[Dean Long]

https://bugs.openjdk.java.net/browse/JDK-8209961
http://cr.openjdk.java.net/~dlong/8209961/webrev/

This change fixes support for -XX:+VerifyOops when used with AOT. The 
feature is disabled in generated AOT code by default unless 
-J-Dgraal.AOTVerifyOops=true
is passed to jaotc (similar idea as --compile-with-assertions).  The JVM 
changes are minimal.  The Graal changes are all from upstream Graal and 
have already been reviewed and pushed there.

dl