RFR: 7903253: sync jextract tests for sequence layout factory split

[Athijegannathan Sundararajan]

Avoid -1 elementCount for Sequence layout factory call.

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Commit messages:
 - 7903253: sync jextract tests for sequence layout factory split

Changes: https://git.openjdk.org/jextract/pull/61/files
 Webrev: https://webrevs.openjdk.org/?repo=jextract&pr=61&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7903253
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jextract/pull/61.diff
  Fetch: git fetch https://git.openjdk.org/jextract pull/61/head:pull/61

PR: https://git.openjdk.org/jextract/pull/61