RFR: 8293416: ZGC: Set mark bit with unconditional atomic ops [v3]

[hev]

> **Summary**
> Support to set ZGC mark bit with unconditional atomic ops.
> 
> **Motivation**
> ZGC currently modify mark-bitmap by a conditional atomic operation (cmpxchg). This way is not optimal, which will retry the loop when cmpxchg fails.
> 
> **Description**
> First, This patch-set add an new unconditional atomic operation: Atomic::fetch_and_or, which is implemented in different ways for different CPU architectures:
> 
> * Exclusive access: Non-nested loop
> 
> 
> retry:
>   ll old_val, addr
>   or new_val, old_val, set_val
>   sc new_val, addr
>   beq retry
> 
> 
> * Atomic access: One instruction
> 
> 
> ldset old_val, set_val, addr
> 
> 
> * Generic: Fallback to cmpxchg or use c++ __atomic_fetch_or
> 
> **Testing**
> * jtreg tests
> * benchmark tests

hev has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:

 - ZGC: Set mark bit with unconditional atomic ops
 - BitMap: Set bit with unconditional atomic ops
 - Atomic: Add bitset functions

-------------

Changes: https://git.openjdk.org/jdk/pull/10182/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10182&range=02
  Stats: 627 lines in 11 files changed: 578 ins; 3 del; 46 mod
  Patch: https://git.openjdk.org/jdk/pull/10182.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10182/head:pull/10182

PR: https://git.openjdk.org/jdk/pull/10182