[vectorIntrinsics] RFR: 8262492: Add cast nodes between float types implementation for Arm SVE [v2]

[Wang Huang]

> Add cast nodes like castf2d castd2f
> 
> * add `sve_fcvt`
> * reuse macro `VECTOR_CAST_I2F_NARROW1` `VECTOR_CAST_I2F_EXTEND1` (Should we change these macro names?)
> 
> other issues :
> * precision loss

Wang Huang has updated the pull request incrementally with one additional commit since the last revision:

  change macro names

-------------

Changes:
  - all: https://git.openjdk.java.net/panama-vector/pull/41/files
  - new: https://git.openjdk.java.net/panama-vector/pull/41/files/f4b15b94..3ba64d04

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=41&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=41&range=00-01

  Stats: 25 lines in 2 files changed: 3 ins; 4 del; 18 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/41.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/41/head:pull/41

PR: https://git.openjdk.java.net/panama-vector/pull/41