[foreign-jextract] [Rev 01] RFR: 8240602: port more tests from old jextract tests

[Athijegannathan Sundararajan]

> * catch RuntimeException around header parser and return failure exit code.
> * add union, (macro) constants and bad bitfield tests.
> * IDE suggested simplyfing refactorings

The pull request has been updated with 1 additional commit.

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Added commits:
 - 19d91382: fixed copyright header for tests.

Changes:
  - all: https://git.openjdk.java.net/panama-foreign/pull/39/files
  - new: https://git.openjdk.java.net/panama-foreign/pull/39/files/0228346a..19d91382

Webrevs:
 - full: https://webrevs.openjdk.java.net/panama-foreign/39/webrev.01
 - incr: https://webrevs.openjdk.java.net/panama-foreign/39/webrev.00-01

  Stats: 16 lines in 6 files changed: 0 ins; 10 del; 6 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/39.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/39/head:pull/39

PR: https://git.openjdk.java.net/panama-foreign/pull/39