RFR: 8290731: Clean up CDS handling of LambdaForm Species classes

[Ioi Lam]

Please see the JBS issue for the reasons for this small clean up.

The main change is in `LambdaFormInvokers::regenerate_holder_classes()` -- do not regenerate the Species_XXX classes. However, mark them as "generated" to be compatible with JVMTI.

I renamed `Klass::is_regenerated()` to `Klass::is_generated_shared_class()` for clarity.

I also updated the test case to be clear what it's trying to do -- Species_IL should be loaded from base archive and Species_JL should be loaded from the dynamic archive.

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

Commit messages:
 - renamed to Klass::is_generated_shared_classs()
 - 8290731: Clean up CDS handling of LambdaForm Species classes

Changes: https://git.openjdk.org/jdk/pull/9577/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9577&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290731
  Stats: 79 lines in 6 files changed: 33 ins; 11 del; 35 mod
  Patch: https://git.openjdk.org/jdk/pull/9577.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9577/head:pull/9577

PR: https://git.openjdk.org/jdk/pull/9577