[Pass] Preserve strided layouts for LLVM backend

[chhzh123]

With memref.subview, we may create some programs like this, which can be directly executed with LLVM backend. However, the current remove-stride-map pass automatically removes those layout maps, causing the error. This PR fixes this issues by only removing the maps describing array partititon.

module {
  func.func @kernel(%arg0: memref<5x10x15xf32>, %arg1: index, %arg2: index) -> memref<15xf32> attributes {itypes = "___", otypes = "_"} {
    %subview = memref.subview %arg0[%arg1, %arg2, 0] [1, 1, 15] [1, 1, 1] : memref<5x10x15xf32> to memref<15xf32, strided<[1], offset: ?>>
    %alloc = memref.alloc() {from = "A"} : memref<15xf32>
    memref.copy %subview, %alloc : memref<15xf32, strided<[1], offset: ?>> to memref<15xf32>
    return %alloc : memref<15xf32>
  }
}