RFR: 8366037: Remove oopDesc::mark_addr() [v2]

[Kim Barrett]

> Please review this change that removes the function oopDesc::mark_addr().
> It's kind of a suspicious function, since it is casting away the volatile for
> a location that has concurrent reads and writes. But there isn't any code that
> examines the value at the obtained address. Instead, it's just used as the
> base address for a few prefetches. We change those places accordingly, and
> remove the now unused mark_addr function.
> 
> Testing: mach5 tier1

Kim Barrett has updated the pull request incrementally with one additional commit since the last revision:

  base_addr

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26914/files
  - new: https://git.openjdk.org/jdk/pull/26914/files/fc5f763b..15b34fcf

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26914&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26914&range=00-01

  Stats: 10 lines in 4 files changed: 6 ins; 1 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/26914.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26914/head:pull/26914

PR: https://git.openjdk.org/jdk/pull/26914