RFR: 8367611: Enable vblendvp[sd] on Future ECore [v3]

[Mohamed Issa]

> The upcoming ECore platforms will benefit from using `vblendvps` and `vblendvpd` instructions when the destination register is the same as the source register. This change takes that situation into account.
> 
> The JTREG test shown below was used to verify correctness against the [OpenJDK v26-b15](https://github.com/openjdk/jdk/releases/tag/jdk-26%2B15) baseline build. This test frequently calls vblendvps() and vblendvpd() in the macro assembler. On Darkmont and non-Darkmont cores, the right code paths are followed when checking with asserts.
> 
> 1. `jtreg:test/hotspot/jtreg/compiler/intrinsics/math/TestSignumIntrinsic.java`

Mohamed Issa has updated the pull request incrementally with one additional commit since the last revision:

  Combine boolean flags to avoid ambiguity

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/27354/files
  - new: https://git.openjdk.org/jdk/pull/27354/files/88ac7733..5e5c0275

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27354&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27354&range=01-02

  Stats: 4 lines in 1 file changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/27354.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27354/head:pull/27354

PR: https://git.openjdk.org/jdk/pull/27354