Missed Optimization: simplify ((x lshr 9) + x) < 256 to x < 256

[Leo0506]

define i1 @src(i32 %arg0) {
  %v0 = lshr i32 %arg0, 9
  %v1 = add nuw i32 %v0, %arg0
  %v2 = icmp ult i32 %v1, 256
  ret i1 %v2
}

define i1 @tgt(i32 %arg0) {
  %v2 = icmp ult i32 %arg0, 256
  ret i1 %v2
}

alive2: https://alive2.llvm.org/ce/z/Ab_dJk
godbolt: https://godbolt.org/z/nYo8114Wq
Pattern found in: https://github.com/dtcxzyw/llvm-opt-benchmark/blob/main/bench/ffmpeg/optimized/webp.ll