RFR: making jextract work with latest panama-foreign repo targetting jdk 20

[Athijegannathan Sundararajan]

making jextract work with latest panama-foreign repo targetting jdk 20

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Commit messages:
 - making jextract work with latest panama-foreign repo targetting jdk 20

Changes: https://git.openjdk.org/jextract/pull/60/files
 Webrev: https://webrevs.openjdk.org/?repo=jextract&pr=60&range=00
  Stats: 483 lines in 118 files changed: 31 ins; 44 del; 408 mod
  Patch: https://git.openjdk.org/jextract/pull/60.diff
  Fetch: git fetch https://git.openjdk.org/jextract pull/60/head:pull/60

PR: https://git.openjdk.org/jextract/pull/60