[vectorIntrinsics] RFR: 8265380: [vector] Perf regression loading/storing short vector from/to char[]

[Paul Sandoz]

While investigating loading/storing byte vector from/to boolean[] i discovered a performance regression loading/storing short vector from/to char[]. I am unsure exactly what caused the regression.

The fix is to refine the checks comparing the element type and the array element type.

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Commit messages:
 - Refine elem to array elem check.

Changes: https://git.openjdk.java.net/panama-vector/pull/69/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=69&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8265380
  Stats: 25 lines in 1 file changed: 23 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/69.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/69/head:pull/69

PR: https://git.openjdk.java.net/panama-vector/pull/69