RFR: 8318913: The module-infos for --release data do not contain pre-set versions

[Jan Lahoda]

Consider a simple module, like:

module test {}


And compile it with JDK 22 and JDK 21 using:
javac --release 21

The results of the compilations will differ: when compiling with JDK 21, the mandated java.base dependency will get a version, possibly like "21-internal". When compiling with JDK 22, the version of the java.base dependency will be empty.

This is a) because `module-info.class`es in `ct.sym` do not have any module version set; b) for JDK N, `--release N` is not using `ct.sym`, but rather `lib/modules`, which may contain a range of version specifiers.

This patch does two changes:
a) tweaks the `module-info.class`es in `ct.sym`, so that they contain a simple version. For `--release N`, the version is `N`.
b) tweaks the whole build so that `ct.sym` is used always for `--release`, a `lib/modules` is never used. I.e. the appropriate classfiles are copied into `ct.sym`. This not only allows for a general approach to module versions, but simplifies the `--release` handling in javac, and should enable future improvements. This is, however, a relatively big change.

The use of `lib/modules` for `--release <current>` was made to improve build performance, but the build has been updated since this has been introduced, so the slowdown caused by rebuilding `ct.sym` should be much lower now.

With these changes, compiling with `--release N` should record the same dependency versions in `module-info` on JDK N and JDK N + 1.

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

Commit messages:
 - Test cleanup.
 - Merge branch 'master' into JDK-8318913
 - Fixing tests.
 - Retain packages for extra classes.
 - Handle permitted subtypes.
 - Fix for writing empty parameter names.
 - Fixing tests.
 - Fixing tests.
 - Cleanup
 - Fixing dependencies
 - ... and 7 more: https://git.openjdk.org/jdk/compare/667cca9d...522d58d6

Changes: https://git.openjdk.org/jdk/pull/16400/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16400&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8318913
  Stats: 554 lines in 11 files changed: 429 ins; 58 del; 67 mod
  Patch: https://git.openjdk.org/jdk/pull/16400.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16400/head:pull/16400

PR: https://git.openjdk.org/jdk/pull/16400