[CIR][AArch64] Add CIR tests for predicated SVE svdup_m builtins (#182307)
This PR adds CIR lowering tests for the predicated SVE `svdup` builtins
on AArch64. The corresponding ACLE intrinsics are documented at:
https://developer.arm.com/architectures/instruction-sets/intrinsics
The tests cover the merging-predicated variants (suffix `_m`, e.g.
`svdup_n_f32_m`). These forms take an explicit inactive-lane value,
which is merged into the result for lanes where the predicate is false.
No functional changes are introduced. The existing lowering
infrastructure already handles these builtins; this change adds
test coverage only.