[jdk20u] RFR: 8278965: crash in SymbolTable::do_lookup

[Calvin Cheung]

Other than a minor conflict in systemDictionary.cpp, the backport is the same as the original fix.

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Commit messages:
 - Backport 582b943439488a0f43482b67c0bc0d4975bf4023

Changes: https://git.openjdk.org/jdk20u/pull/11/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk20u&pr=11&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8278965
  Stats: 120 lines in 3 files changed: 117 ins; 1 del; 2 mod
  Patch: https://git.openjdk.org/jdk20u/pull/11.diff
  Fetch: git fetch https://git.openjdk.org/jdk20u pull/11/head:pull/11

PR: https://git.openjdk.org/jdk20u/pull/11