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

[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.

1. `jtreg:test/hotspot/jtreg/compiler/intrinsics/math/TestSignumIntrinsic.java`

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Commit messages:
 - Add file missing from last commit
 - Use blend instruction when destination is same as source for certain ECore platforms

Changes: https://git.openjdk.org/jdk/pull/27354/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27354&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8367611
  Stats: 14 lines in 3 files changed: 12 ins; 0 del; 2 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