RFR: 8375241: Simplify --with-native-debug-symbols-level option implementation [v3]

[Julian Waters]

> --with-native-debug-symbols-level was added some time ago to allow selecting the level of debugging information created for compiled binaries. The UTIL_ARG_WITH utility that the option implementation uses has several features that can be used to simplify handling of this option, so that is done in this change.

Julian Waters has updated the pull request incrementally with one additional commit since the last revision:

  Use auto for default in flags-cflags.m4

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/29214/files
  - new: https://git.openjdk.org/jdk/pull/29214/files/d6a1e78d..37d8c9f4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29214&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29214&range=01-02

  Stats: 10 lines in 1 file changed: 0 ins; 3 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/29214.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29214/head:pull/29214

PR: https://git.openjdk.org/jdk/pull/29214