[MLIR][OpenMP] Lowering aligned clause to LLVM IR for SIMD directive (#119536)
This patch,
- Added a translation support for aligned clause in SIMD directive by passing the alignment details to "llvm.assume" intrinsic.
- Updated the insertion point for llvm.assume intrinsic call in "OMPIRBuilder.cpp".
- Added a check in aligned clause MLIR lowering, to ensure that the alignment value must be a power of 2.