RFR: 8357179: Deprecate VFORK launch mechanism from Process implementation (linux) [v2]

[Thomas Stuefe]

> For the ratio behind this please see the companion CSR: https://bugs.openjdk.org/browse/JDK-8357180.
> 
> We plan to deprecate this in JDK 25 and to remove it in JDK 26.
> 
> This patch just writes a deprecation message to stderr:
> 
> 
> 08:46:38 thomas at starfish java -Djdk.lang.Process.launchMechanism=VFORK SimpleSpawn ls
> VFORK MODE DEPRECATED
> The VFORK launch mechanism has been deprecated for being dangerous.
> It will be removed in a future java version. Either remove the
> jdk.lang.Process.launchMechanism property (preferred) or use FORK mode
> instead (-Djdk.lang.Process.launchMechanism=FORK).
> ...

Thomas Stuefe has updated the pull request incrementally with one additional commit since the last revision:

  use string block

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/25282/files
  - new: https://git.openjdk.org/jdk/pull/25282/files/8bd4a36e..ec3197f9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25282&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25282&range=00-01

  Stats: 6 lines in 1 file changed: 2 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/25282.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25282/head:pull/25282

PR: https://git.openjdk.org/jdk/pull/25282