RFR: 8259846: [BACKOUT] JDK-8259278 Optimize Vector API slice and unslice operations

[Daniel D.Daugherty]

This reverts commit a6b2162f5400b4596afa5b88219c9cb55dcdb729.

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Commit messages:
 - 8259846: [BACKOUT] JDK-8259278 Optimize Vector API slice and unslice operations

Changes: https://git.openjdk.java.net/jdk/pull/2103/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2103&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8259846
  Stats: 983 lines in 45 files changed: 523 ins; 266 del; 194 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2103.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2103/head:pull/2103

PR: https://git.openjdk.java.net/jdk/pull/2103