RFR: 8285914: AppCDS crash when using shared archive with old class file from JUnit

[Calvin Cheung]

Please review this change for an additional check before archiving a lambda proxy class. If the nest host of an lambda proxy class cannot be verified during dump time due to its major version is < JDK_6 (50), the lambda proxy class should not be archived. This avoids accessing a null nest host during runtime while loading the lambda proxy class from the CDS archive.

Passed the test in the bug report.

Passed CI tiers 1 - 4 testing (including the new tests).

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Commit messages:
 - 8285914: AppCDS crash when using shared archive with old class file from JUnit

Changes: https://git.openjdk.java.net/jdk/pull/8540/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8540&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8285914
  Stats: 220 lines in 5 files changed: 218 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8540.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8540/head:pull/8540

PR: https://git.openjdk.java.net/jdk/pull/8540