RFR: 8346778: Enable native access should work with the source launcher [v2]

[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 one additional commit since the last revision:

  Ignore already handled `ALL-UNNAMED` name

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22930/files
  - new: https://git.openjdk.org/jdk/pull/22930/files/670e8647..7c615966

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22930&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22930&range=00-01

  Stats: 16 lines in 2 files changed: 9 ins; 0 del; 7 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