RFR: 8352635: Improve inferencing of Float16 operations with constant inputs [v6]

[Jatin Bhateja]

> This is a follow-up PR#22755 to improve Float16 operations inferencing.
> 
> The existing scheme to detect Float16 operations for some operations is based on pattern matching which expects to receive inputs through ConvHF2F IR, this patch extends matching to accept constant floating point inputs within the Float16 value range.
> 
> Best Regards,
> Jatin

Jatin Bhateja has updated the pull request incrementally with three additional commits since the last revision:

 - Update test/hotspot/jtreg/compiler/lib/generators/Generators.java
   
   Co-authored-by: Emanuel Peter <emanuel.peter at oracle.com>
 - Update src/hotspot/share/opto/convertnode.cpp
   
   Co-authored-by: Emanuel Peter <emanuel.peter at oracle.com>
 - Update src/hotspot/share/opto/convertnode.cpp
   
   Co-authored-by: Emanuel Peter <emanuel.peter at oracle.com>

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/24179/files
  - new: https://git.openjdk.org/jdk/pull/24179/files/4a491bef..b95c51cb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24179&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24179&range=04-05

  Stats: 14 lines in 2 files changed: 2 ins; 2 del; 10 mod
  Patch: https://git.openjdk.org/jdk/pull/24179.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24179/head:pull/24179

PR: https://git.openjdk.org/jdk/pull/24179