RFR: JDK-8324598: use mem_unit when working with sysinfo memory and swap related information [v2]

[Matthias Baesken]

> According to the sysinfo manpage ( https://man7.org/linux/man-pages/man2/sysinfo.2.html ) the memory and swap related entries in the struct sysinfo are given as multiples of mem_unit bytes.
> "In the above structure, sizes of the memory and swap fields are given as multiples of mem_unit bytes."
> 
> This is considered in most parts of the OpenJDK codebase when sysinfo is used but not all; should be added where it is missing.

Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:

  add parentheses

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Changes:
  - all: https://git.openjdk.org/jdk/pull/17550/files
  - new: https://git.openjdk.org/jdk/pull/17550/files/c46b804f..77b2d44e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17550&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17550&range=00-01

  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/17550.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17550/head:pull/17550

PR: https://git.openjdk.org/jdk/pull/17550