RFR (S) CR 8008965: @Contended fails with classes having static fields

[Aleksey Shipilev]

Hi,

The jsr166 testing shows @Contended fails with the classes having the
static fields. The bottom line for the issue is that HS maintains
contiguous area of static oops within the class, and injecting padding
there breaks the field walk logic.

This does not break the usual builds, because that code is not used
unless you have @Contended classes (in some regard, that's why it
slipped testing before).

Fixing @Contended to work with static fields will require substantial
amount of redo in static oops map code, so at this point it seems
beneficial to just no-op the @Contended effect for static fields:
  http://cr.openjdk.java.net/~shade/8008965/webrev.00/

Our primary use cases involve instance fields, so this shoves off the
low priority functionality. After we commit this fix, does anyone has
the problem with doing static oops maps in the same way we deal with
instance oops maps in the class?

Testing:
  - full JPRT cycle with hotspot-rt
  - targeted jsr166 builds with @Contended
  - 8003985 regression test

-Aleksey.