[jdk21u-dev] RFR: 8334738: os::print_hex_dump should optionally print ASCII

[Thomas Stuefe]

This backports a small new feature down to jdk 21u: The ability to print ASCII portions alongside hex portions in hotspot hex dump.

This has been very useful recently with CDS archive analysis in the context of reproducible builds (figuring out  which parts of the dump make archive generation non-reproducible). Since this is very much a topic for JDK 21, I would be happy if we could backport it.

The backport consists of two patches:
- one for [JDK-8334738](https://bugs.openjdk.org/browse/JDK-8334738)
- a small follow-up fix for Big Endian platforms: [JDK-8335906](https://bugs.openjdk.org/browse/JDK-8335906)

Unfortunately, [JDK-8334738](https://bugs.openjdk.org/browse/JDK-8334738) does not apply cleanly to JDK 23 because of some intermediate cleanup patches that are missing from JDK21 and possibly too large to backport:

- 8314752: Use google test string comparison macros
- 8313882: Fix -Wconversion warnings in runtime code

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

Commit messages:
 - cherry-pick 8335906
 - fix conflicts
 - Backport 8334738 with CONFLICTS

Changes: https://git.openjdk.org/jdk21u-dev/pull/855/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=855&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8334738
  Stats: 160 lines in 7 files changed: 68 ins; 15 del; 77 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/855.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/855/head:pull/855

PR: https://git.openjdk.org/jdk21u-dev/pull/855