RFR: 8364532: G1: In liveness tracing, print more significant digits for the liveness value [v4]

[Thomas Schatzl]

> Hi all,
> 
>   please review this small change that adds some more significant digits (3 in total) for the "liveness" column in collection set group logging.
> 
> E.g. see the emphasized columns that lack precision (it's more irritating with lots of lines showing single-digit values):
> 
> 50.707s][trace][gc,liveness] GC(13) ### groud-id num-regions gc-eff liveness remset type
> 50.707s][trace][gc,liveness] GC(13) ### (bytes/ms) % (bytes)
> 50.707s][trace][gc,liveness] GC(13) ### 1 70       0.0 *100* 3199208 Y
> 50.707s][trace][gc,liveness] GC(13) ### 2 51 5298129.5  *18* 1224072 M
> 50.707s][trace][gc,liveness] GC(13) ### 3  5 3223983.6  *31*  176648 M
> 50.707s][trace][gc,liveness] GC(13) ### 4  5 3022016.3  *32*  176648 M
> 
> 
> (This depends on PR#26591, so please look at that one first).
> 
> The change makes sure that three significant digits are printed.
> 
> Testing: manual review
> 
> Thanks,
>   Thomas

Thomas Schatzl has updated the pull request incrementally with one additional commit since the last revision:

  * ayang suggestion to avoid exponential output

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26595/files
  - new: https://git.openjdk.org/jdk/pull/26595/files/2da72ca3..96f895dd

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26595&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26595&range=02-03

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/26595.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26595/head:pull/26595

PR: https://git.openjdk.org/jdk/pull/26595