[clang] [llvm] [AArch64] Implement NEON vscale intrinsics (PR #100347)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `arc-builder` running on `arc-worker` while building `clang,llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/3/builds/5294

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang :: CodeGen/aarch64-neon-fp8-intrinsics/acle_neon_fscale.c' FAILED ********************
Exit Code: 2

Command Output (stderr):
--
RUN: at line 4: /buildbot/worker/arc-folder/build/bin/clang -cc1 -internal-isystem /buildbot/worker/arc-folder/build/lib/clang/20/include -nostdsysteminc -triple aarch64-none-linux-gnu -target-feature +neon -target-feature +fp8 -O3 -emit-llvm -o - /buildbot/worker/arc-folder/llvm-project/clang/test/CodeGen/aarch64-neon-fp8-intrinsics/acle_neon_fscale.c | /buildbot/worker/arc-folder/build/bin/FileCheck /buildbot/worker/arc-folder/llvm-project/clang/test/CodeGen/aarch64-neon-fp8-intrinsics/acle_neon_fscale.c
+ /buildbot/worker/arc-folder/build/bin/clang -cc1 -internal-isystem /buildbot/worker/arc-folder/build/lib/clang/20/include -nostdsysteminc -triple aarch64-none-linux-gnu -target-feature +neon -target-feature +fp8 -O3 -emit-llvm -o - /buildbot/worker/arc-folder/llvm-project/clang/test/CodeGen/aarch64-neon-fp8-intrinsics/acle_neon_fscale.c
/buildbot/worker/arc-folder/llvm-project/clang/test/CodeGen/aarch64-neon-fp8-intrinsics/acle_neon_fscale.c:2:10: fatal error: 'arm_neon.h' file not found
    2 | #include <arm_neon.h>
      |          ^~~~~~~~~~~~
+ /buildbot/worker/arc-folder/build/bin/FileCheck /buildbot/worker/arc-folder/llvm-project/clang/test/CodeGen/aarch64-neon-fp8-intrinsics/acle_neon_fscale.c
1 error generated.
FileCheck error: '<stdin>' is empty.
FileCheck command line:  /buildbot/worker/arc-folder/build/bin/FileCheck /buildbot/worker/arc-folder/llvm-project/clang/test/CodeGen/aarch64-neon-fp8-intrinsics/acle_neon_fscale.c

--

********************


```

</details>

https://github.com/llvm/llvm-project/pull/100347