[vectorIntrinsics+mask] RFR: 8272869: AArch64: Mark masked rearrange operation as unsupported

[Eric Liu]

This patch marks masked rearrange operation as unsupported for AArch64,
the reasons are as follows:

1. AArch64 dose not have predicated 'tbl' instruction
2. Mid-end has transformed masked VectorRearrange into VectorBlend[1]
   for those platforms which are missing corresponding instructions.

Given by this, there's no need to add backend support for masked
VectorRearrange, and the final generated code as below:


        tbl     z16.s, {z20.s}, z16.s
        mov     z17.s, #0
        sel     z16.s, p2, z16.s, z17.s


[1] https://github.com/openjdk/panama-vector/blob/vectorIntrinsics%2Bmask/src/hotspot/share/opto/vectorIntrinsics.cpp#L2016

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Commit messages:
 - 8272869: AArch64: Mark masked rearrange operation as unsupported

Changes: https://git.openjdk.java.net/panama-vector/pull/118/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=118&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8272869
  Stats: 16 lines in 2 files changed: 4 ins; 8 del; 4 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/118.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/118/head:pull/118

PR: https://git.openjdk.java.net/panama-vector/pull/118