RFR: 8314488: Compile the JDK as C++17

[Martin Doerr]

On Mon, 24 Jul 2023 01:41:16 GMT, Julian Waters <jwaters at openjdk.org> wrote:

> Implementation of [JEP draft: Compile the JDK as C++17](https://bugs.openjdk.org/browse/JDK-8310260)

Successfully tested on AIX with xlc 17.1.1. Works for us (SAP). Please check with others who might still use an older compiler (IBM).

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Marked as reviewed by mdoerr (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/14988#pullrequestreview-1586571119