RFR: 8338747: hasIncubatorModules needs to be generated when module resolution required at startup

[Alan Bateman]

This PR proposes changes to the ModuleBootstrap code that is used with CDS (Ahead-of-Time Class Loading & Linking in the future). At things stand, the module graph and boot layer can be archived at dump time (-Xshare:dump) when the initial module is the class path or the initial module is in the run-time image. Future work will extend this to deployments with an application module path or where additional root modules are specified with --add-modules. To get there we need the code that determines whether to archive is in one place, and it needs to know if the module graph contains incubator modules or split packages. 

Testing: tier1-tier6. There are no new tests, the changes don't expand or change what can be archived. Calvin has done some some testing with the change as it is needed for [JDK-8328313](https://bugs.openjdk.org/browse/JDK-8328313).

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Commit messages:
 - Merge
 - Merge
 - Cleanup
 - Merge
 - Merge
 - Initial commit

Changes: https://git.openjdk.org/jdk/pull/20818/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20818&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8338747
  Stats: 72 lines in 1 file changed: 31 ins; 21 del; 20 mod
  Patch: https://git.openjdk.org/jdk/pull/20818.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20818/head:pull/20818

PR: https://git.openjdk.org/jdk/pull/20818