RFR: 8305995: Use full dominant search for regions [v2]

[Kirill A. Korinsky]

> This is a fix for the regression introduced by da43cb5e463069cf4dafb262664f0d3d7c2e0eac in fix 8224957.
> 
> This regression was found while attempting to migrate an application from JDK 1.8 to JDK 17, by running internal benchmarks, and while investigating abnormal memory usage for about 4 times more from one of them.
> 
> The regression appears in the JMH benchmark, which builds a huge tree which contains boxed integers from 0 to a few thousand. A tree has very complex structure and the same objects are reused a lot.
> 
> When an `integer` is found it's collected as `Integer` and unboxed inside the collector callback.
> 
> This benchmark was run with `ParallelGC` on different JVMs: `JDK 1.8.0_362`, `JDK 11.0.18`, `JDK 13.0.13`, `JDK 15.0.9`, `JDK 17.0.6`, `JDK 19.0.2` and `JDK 20`. This allows to see that something has changed between 13 and 15, and that the memory footprint for this code has increased from `3152` to `11828` bytes per operation.
> 
> After that I've done a `git bisect` which allows me to locate the introducer.
> 
> So the current fix reduces the memory footprint on the local root 425ef0685c584abec80454fbcccdcc6db6558f93 to `2960` bytes per operation.

Kirill A. Korinsky has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:

  8305995: Use full dominant search for regions
  
  This is a fix for the regression introduced by
  da43cb5e463069cf4dafb262664f0d3d7c2e0eac in fix 8224957.
  
  This regression was found while attempting to migrate an application
  from JDK 1.8 to JDK 17, by running internal benchmarks, and while
  investigating abnormal memory usage for about 4 times more from one of
  them.
  
  The regression appears in provided JMH benchmark, which builds a RB-tree
  based map which contains 780 entries with primitive integers.
  
  This benchmark was run with `ParallelGC` on different JVMs: `JDK
  1.8.0_362`, `JDK 11.0.18`, `JDK 13.0.13`, `JDK 15.0.9`, `JDK 17.0.6`,
  `JDK 19.0.2` and `JDK 20`. This allows to see that something has changed
  between 13 and 15, and that the memory footprint for this code has
  increased from nothing `≈ 10⁻³ ` to `7536` bytes per operation.
  
  Proposed fix reduces the memory footprint expected value.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/13453/files
  - new: https://git.openjdk.org/jdk/pull/13453/files/82c77579..dbc3ebf9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13453&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13453&range=00-01

  Stats: 1203 lines in 1 file changed: 1203 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/13453.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13453/head:pull/13453

PR: https://git.openjdk.org/jdk/pull/13453