[jdk21u-dev] RFR: 8322159: ThisEscapeAnalyzer crashes for erroneous code

[Aleksey Shipilev]

Clean backport to fix a javac corner case.

Additional testing:
 - [x] New regression test fails without the fix, passes with it
 - [x] macos-aarch64-server-fastdebug, `langtools_all`

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Commit messages:
 - Backport 7455b1b527568aff5b1c16a29fd80b05260c0fad

Changes: https://git.openjdk.org/jdk21u-dev/pull/117/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=117&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8322159
  Stats: 44 lines in 2 files changed: 41 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/117.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/117/head:pull/117

PR: https://git.openjdk.org/jdk21u-dev/pull/117