[vectorIntrinsics] RFR: 8263348: Add cast nodes from double precision float types to interger types implementation for Arm SVE

[Wang Huang]

Add cast nodes from double precision float types to interger types implementation for Arm SVE
* add CASTD2B/ CASTD2S/ CASTD2I/CASTD2L

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Commit messages:
 - 8263348: Add cast nodes from double precision float types to interger types implementation for Arm SVE

Changes: https://git.openjdk.java.net/panama-vector/pull/47/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=47&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8263348
  Stats: 103 lines in 2 files changed: 103 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/47.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/47/head:pull/47

PR: https://git.openjdk.java.net/panama-vector/pull/47