RFR: 8314488: Compiling the JDK with C++17 [v2]

[Kim Barrett]

> Please review this change to use C++17 for building C++ parts of the JDK. In
> particular this affects HotSpot. This change also includes an update to the
> HotSpot Style Guide regarding C++17 features and their use in HotSpot code.
> 
> Testing: mach5 tier1-8
> 
> This change includes a modification of the Style Guide. Rough consensus among
> the HotSpot Group members is required to make such a change. Only Group
> members should vote for approval (via the github PR), though reasoned
> objections or comments from anyone will be considered. A decision on this
> proposal will not be made before Friday 5-September-2025 at 12h00 UTC.
> 
> Since we're piggybacking on github PRs here, please use the PR review process
> to approve (click on Review Changes > Approve), rather than sending a "vote:
> yes" email reply that would be normal for a CFV.

Kim Barrett has updated the pull request incrementally with one additional commit since the last revision:

  fix missing word

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26884/files
  - new: https://git.openjdk.org/jdk/pull/26884/files/0876cacd..cdd11cce

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26884&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26884&range=00-01

  Stats: 3 lines in 2 files changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/26884.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26884/head:pull/26884

PR: https://git.openjdk.org/jdk/pull/26884