[jdk11u-dev] RFR: 8231501: VM crash in MethodData::clean_extra_data(CleanExtraDataClosure*): fatal error: unexpected tag 99

[Martin Doerr]

Backport of JDK-8231501. Applies almost cleanly. Only one comment change had to get integrated manually due to unrelated context change.

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Depends on: https://git.openjdk.java.net/jdk11u-dev/pull/434

Commit messages:
 - Backport 49048adcf206034e8cfe2877029bfa5523c9eb4c

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/435/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=435&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8231501
  Stats: 69 lines in 3 files changed: 44 ins; 16 del; 9 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/435.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/435/head:pull/435

PR: https://git.openjdk.java.net/jdk11u-dev/pull/435