[vectorIntrinsics+fp16] RFR: Merge vectorIntrinsics [v2]

[Jatin Bhateja]

> Merge vectorIntrinsics into vectorIntrinsics+fp16 as per the proposal on panama-dev mailing list[1]. This was a major merge after a gap of 2+ years.
> 
> Summary of changes:-
>    - Added a new package-private field CTYPE (carrier type) along with existing ETYPE (element type) to differentiate b/w the storage type from the vector lane element type.
>    - Pass an explicit operType argument to inline expanders to ease inferencing of Float16 vector IR. Idea: leverage existing backend implementation added along with JDK-8346236[2] and [3]
>    - Appropriate modifications in existing inline expansion entry points and VectorSupport class.
>    - Replaced existing Halffloat class references with jdk.incubator.vector.Float16, along with appropriate API adjustments.
>   
> What is remaining:-
>   -    Use the newly passed operType to infer Float16 Vector IR.
>   -    Functional validation
>   - Performance validation
>  
> [1] https://mail.openjdk.org/pipermail/panama-dev/2025-August/021100.html
> [2] https://github.com/openjdk/jdk/pull/22755
> [3] https://github.com/openjdk/jdk/pull/22754

Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:

  Bug fixes for conversion APIs

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

Changes:
  - all: https://git.openjdk.org/panama-vector/pull/230/files
  - new: https://git.openjdk.org/panama-vector/pull/230/files/ba58e0ea..0c3d1cda

Webrevs:
 - full: Webrev is not available because diff is too large
 - incr: https://webrevs.openjdk.org/?repo=panama-vector&pr=230&range=00-01

  Stats: 723 lines in 48 files changed: 281 ins; 76 del; 366 mod
  Patch: https://git.openjdk.org/panama-vector/pull/230.diff
  Fetch: git fetch https://git.openjdk.org/panama-vector.git pull/230/head:pull/230

PR: https://git.openjdk.org/panama-vector/pull/230