RFR (S) 8219459: oopDesc::is_valid() is broken

[coleen.phillimore at oracle.com]

Summary: Use Metaspace::contains() to test address ranges.

Tested with hs-tier1-3, and all tier1 on linux-x64-debug.  Tested 
manually in gdb.

open webrev at http://cr.openjdk.java.net/~coleenp/2019/8219459.01/webrev
bug link https://bugs.openjdk.java.net/browse/JDK-8219459

Thanks,
Coleen