[lworld] RFR: 8376088: [lworld] value class creation in CompileJavaModules.gmk leaves unnecessary files

[David Beaumont]

This is a tidying up of the value class generation and management.
It solves JDK-8376088, but also simplifies the two-step process for creating the `META-INF/preview` class files.

Short description of changes:
1. Remove JAR file creation (no longer needed, this is the proximal fix for JDK-8376088).
2. Stop adding the "intermediate" target for the compilation to the TARGETS list (rely on the subsequent move).
3. Move directories directly from the output directory to the preview directory (does not move marker files).
4. Make the marker file appear alongside other markers for the module compilation.
5. Rename marker file to be consistent with other sibling marker files.

The marker files in `build/linux-x64/jdk/modules/java.base/` are now:


_the.java.base_batch
_the.java.base_batch.cmdline
_the.java.base_batch.filelist
_the.java.base_batch.log
_the.java.base_batch.modfiles
_the.java.base_batch.modfiles.fixed
_the.java.base.config_vardeps
_the.java.base_internalapi
_the.java.base-javacserver.conf
_the.java.base_pubapi
_the.java.base.valueclasses   <-- moved/renamed mark file
_the.java.base.vardeps


I've added a couple of notes where there could be choices about the implementation.

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

Commit messages:
 - Tidying makefile related to value classes

Changes: https://git.openjdk.org/valhalla/pull/1949/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1949&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8376088
  Stats: 40 lines in 1 file changed: 9 ins; 20 del; 11 mod
  Patch: https://git.openjdk.org/valhalla/pull/1949.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1949/head:pull/1949

PR: https://git.openjdk.org/valhalla/pull/1949