RFR: 8222558: Rework ResolvedMethodTable verification

[Stefan Karlsson]

Hi all,

Please review this patch to rework the ResolvedMethodTable verification.

https://cr.openjdk.java.net/~stefank/8222558/webrev.01/
https://bugs.openjdk.java.net/browse/JDK-8222558

The patch removes the quadratic search for duplicate entries, and adds a 
linear scan that checks that the vmtargets are non-old methods. The 
verification is moved to be run when Universe::verify is called.

Testing tier1-3.

Thanks,
StefanK