RFR: 8346778: Enable native access should work with the source launcher [v3]

[Christian Stein]

> Please review this change request enabling native access in source launch mode when using a modular setup.
> 
> The change comes in two parts:
> 1. Prevent warnings of unknown modules being emitted from module bootstrap for user module not being present in the boot layer: `java.c` and `ModuleBootstrap.java`
> 2. Enable native access in source module(s) and also user modules on the module path as requested by `--enable-native-access` via the `ModuleLayer.Controller` API - and emit warning for unknown modules: `MemoryContext.java`
> 
> _Testing of tier1..3 is in progress..._

Christian Stein has updated the pull request incrementally with three additional commits since the last revision:

 - Update src/java.base/share/classes/jdk/internal/module/ModuleBootstrap.java
 - Update src/java.base/share/native/libjli/java.c
   
   [skip ci]
 - Update src/java.base/share/classes/jdk/internal/module/ModuleBootstrap.java
   
   [skip ci]

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22930/files
  - new: https://git.openjdk.org/jdk/pull/22930/files/7c615966..6ff0cd30

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22930&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22930&range=01-02

  Stats: 5 lines in 2 files changed: 0 ins; 0 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/22930.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22930/head:pull/22930

PR: https://git.openjdk.org/jdk/pull/22930