RFR: 8051680: (ref) unnecessary process_soft_ref_reconsider [v2]

[Albert Mingkun Yang]

> This PR consists of 3 commits:
> 
> 1. Removes the soft-ref reconsideration phase because the soft-ref policy is set before marking (JDK-8269596) and stays the same across the GC cycle. Reconsideration phase should not find anything interesting. That being said, there might be some benefit of using more precise heap usage after marking for soft-ref processing, created JDK-8269798 for exploring that.
> 
> 2. Removes reloading of `_soft_ref_timestamp_clock` from `java_lang_ref_SoftReference::clock();` because the master clock should only be changed by GC.
> 
> 3. Rename phase{2,3,4} to phase{1,2,3}.
> 
> Test: hotspot_gc

Albert Mingkun Yang has updated the pull request incrementally with one additional commit since the last revision:

  Revert "rename"
  
  This reverts commit 740e18530eae4be0824398c156ae4ce3634b4e1e.

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4667/files
  - new: https://git.openjdk.java.net/jdk/pull/4667/files/740e1853..22d5605d

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4667&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4667&range=00-01

  Stats: 86 lines in 5 files changed: 10 ins; 10 del; 66 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4667.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4667/head:pull/4667

PR: https://git.openjdk.java.net/jdk/pull/4667