RFR: 8325438: Add exhaustive tests for Math.round intrinsics [v5]

[Hamlin Li]

> HI,
> Can you have a look at this patch adding some tests for Math.round instrinsics?
> Thanks!
> 
> ### FYI:
> During the development of RoundVF/RoundF, we faced the issues which were only spotted by running test exhaustively against 32/64 bits range of int/long.
> It's helpful to add these exhaustive tests in jdk for future possible usage, rather than build it everytime when needed.
> Of course, we need to put it in `manual` mode, so it's not run when `-automatic` jtreg option is specified which I guess is the mode CI used, please correct me if I'm assume incorrectly.

Hamlin Li has updated the pull request incrementally with one additional commit since the last revision:

  add comments; refine code

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/17753/files
  - new: https://git.openjdk.org/jdk/pull/17753/files/e1127c76..2afa8160

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17753&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17753&range=03-04

  Stats: 36 lines in 2 files changed: 24 ins; 6 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/17753.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17753/head:pull/17753

PR: https://git.openjdk.org/jdk/pull/17753