RFR (S) 8228753: Deprecate -XX:FieldsAllocationStyle product option and CompactiFields

[coleen.phillimore at oracle.com]

8228753: Deprecate -XX:FieldsAllocationStyle product option
8228749: Deprecate product flag -XX:CompactFields

CSRs approved.  See bug and link for more details.  Ran tier1-3 on 
linux-x64-debug.

open webrev at http://cr.openjdk.java.net/~coleenp/2019/8228753.01/webrev
bug link https://bugs.openjdk.java.net/browse/JDK-8228753

Thanks,
Coleen