RFR: 8350770: [BACKOUT] Protection zone for easier detection of accidental zero-nKlass use

[Thomas Stuefe]

Please review this backout of JDK-8330174; it broke several tests at SAP and Oracle. See https://bugs.openjdk.org/browse/JDK-8350768.

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Commit messages:
 - Revert "8330174: Protection zone for easier detection of accidental zero-nKlass use"

Changes: https://git.openjdk.org/jdk/pull/23799/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23799&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8350770
  Stats: 426 lines in 16 files changed: 29 ins; 331 del; 66 mod
  Patch: https://git.openjdk.org/jdk/pull/23799.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23799/head:pull/23799

PR: https://git.openjdk.org/jdk/pull/23799