RFR: 8259610: VectorReshapeTests are not effective due to failing to intrinsify "VectorSupport.convert"

[Mai Đặng Quân Anh]

Hi,

This patch adds several c2 tests for vector reshape operations. The tests verify the intrinsification of the corresponding operations by using the IR framework and verify the correctness of the results of compiled codes.

While working on this patch, I spot some regressions regarding compilation on AVX1.

Thank you very much.

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Commit messages:
 - grammar in comment
 - missing copyright
 - add comments
 - vector reshape compiler tests
 - Merge branch 'master' into vectorReshapeTests
 - initial commit

Changes: https://git.openjdk.java.net/jdk/pull/6724/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6724&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8259610
  Stats: 4097 lines in 15 files changed: 4097 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6724.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6724/head:pull/6724

PR: https://git.openjdk.java.net/jdk/pull/6724