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

[Wang Huang]

* add sve_fcvtzs & sve_fcvtzu
* add F2I F2S F2B F2L
* change macro name `VECTOR_CAST_I2F` -> `VECTOR_CAST_X2X` for that we reuse it.

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

Changes: https://git.openjdk.java.net/panama-vector/pull/46/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=46&range=00
  Stats: 260 lines in 5 files changed: 193 ins; 0 del; 67 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/46.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/46/head:pull/46

PR: https://git.openjdk.java.net/panama-vector/pull/46