[foreign-jextract] RFR: 8266682: sync jextract for LibraryLookup removal

[Athijegannathan Sundararajan]

Using System.load/.loadLibrary in generated code and jextract code. Class initialisation dummy method to take sure constants classes initialise header-class before looking up names.

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Commit messages:
 - 8266682: sync jextract for LibraryLookup removal

Changes: https://git.openjdk.java.net/panama-foreign/pull/529/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=529&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8266682
  Stats: 420 lines in 7 files changed: 32 ins; 21 del; 367 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/529.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/529/head:pull/529

PR: https://git.openjdk.java.net/panama-foreign/pull/529