[foreign-jextract] RFR: 8244412: jextract should generate static utils class for primitive typedefs

[Athijegannathan Sundararajan]

generating static utils classes for (subset of) primitive typedef trees.

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Commit messages:
 - add one more test for primitive typedef usage.
 - 8244412: jextract should generate static utils class for primitive typedefs

Changes: https://git.openjdk.java.net/panama-foreign/pull/144/files
 Webrev: https://webrevs.openjdk.java.net/panama-foreign/144/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8244412
  Stats: 216 lines in 8 files changed: 198 ins; 0 del; 18 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/144.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/144/head:pull/144

PR: https://git.openjdk.java.net/panama-foreign/pull/144