RFR: 8307518: Remove G1 workaround in jstat about zero sized generation sized [v2]

[Thomas Schatzl]

> Hi all,
> 
>   please review removal of some workaround in g1 memory usage monitoring that made sure that there were no 0-sized generations in the output. After [JDK-8307428](https://bugs.openjdk.org/browse/JDK-8307428) this is not necessary any more.
> 
> Testing: tier1-5
> 
> Thanks,
>   Thomas

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

  minor fixes to indentation

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/13880/files
  - new: https://git.openjdk.org/jdk/pull/13880/files/6af87816..fba26bf6

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13880&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13880&range=00-01

  Stats: 30 lines in 1 file changed: 10 ins; 0 del; 20 mod
  Patch: https://git.openjdk.org/jdk/pull/13880.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13880/head:pull/13880

PR: https://git.openjdk.org/jdk/pull/13880