RFR: 8365594: Strengthen Universe klasses asserts to catch bootstrapping errors earlier

[Aleksey Shipilev]

I am chasing a Shenandoah + CDS bootstrapping problem, where Shenandoah tries to insert the filler at the time when Universe is not yet initialized. It currently fails rather cryptically on attempt to store `null` class. We could really use an assert on accessing various `Klass` definitions in Universe.

We already do this for `TypeArrayKlass-es`, so this change would cover `fillerArrayKlass` and `objectArrayKlass`. 

Additional testing:
 - [x] Shenandoah + CDS reproducer crashes reliably
 - [x] Linux AArch64 server fastdebug, `all`

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Commit messages:
 - Fix

Changes: https://git.openjdk.org/jdk/pull/26797/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26797&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8365594
  Stats: 14 lines in 2 files changed: 9 ins; 1 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/26797.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26797/head:pull/26797

PR: https://git.openjdk.org/jdk/pull/26797