RFR: 8331671: Implement JEP 472: Prepare to Restrict the Use of JNI [v4]

[Maurizio Cimadamore]

> This PR implements [JEP 472](https://openjdk.org/jeps/472), by restricting the use of JNI in the following ways:
> 
> * `System::load` and `System::loadLibrary` are now restricted methods
> * `Runtime::load` and `Runtime::loadLibrary` are now restricted methods
> * binding a JNI `native` method declaration to a native implementation is now considered a restricted operation
> 
> This PR slightly changes the way in which the JDK deals with restricted methods, even for FFM API calls. In Java 22, the single `--enable-native-access` was used both to specify a set of modules for which native access should be allowed *and* to specify whether illegal native access (that is, native access occurring from a module not specified by `--enable-native-access`) should be treated as an error or a warning. More specifically, an error is only issued if the `--enable-native-access flag` is used at least once.
> 
> Here, a new flag is introduced, namely `illegal-native-access=allow/warn/deny`, which is used to specify what should happen when access to a restricted method and/or functionality is found outside the set of modules specified with `--enable-native-access`. The default policy is `warn`, but users can select `allow` to suppress the warnings, or `deny` to cause `IllegalCallerException` to be thrown. This aligns the treatment of restricted methods with other mechanisms, such as `--illegal-access` and the more recent `--sun-misc-unsafe-memory-access`.
> 
> Some changes were required in the package-info javadoc for `java.lang.foreign`, to reflect the changes in the command line flags described above.

Maurizio Cimadamore has updated the pull request incrementally with two additional commits since the last revision:

 - Address review comments
   Improve warning for JNI methods, similar to what's described in JEP 472
   Beef up tests
 - Address review comments

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19213/files
  - new: https://git.openjdk.org/jdk/pull/19213/files/bad10942..0d21bf99

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19213&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19213&range=02-03

  Stats: 84 lines in 15 files changed: 42 ins; 14 del; 28 mod
  Patch: https://git.openjdk.org/jdk/pull/19213.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19213/head:pull/19213

PR: https://git.openjdk.org/jdk/pull/19213