modify nearest_interpolate when attr align_corners=false (bug_fix) (#1969)

* modify slice op and add slice test

* modify nearest_polate when align_corners=false (bugfix)

lite/backends/arm/math/interpolate.cc

@@ -459,8 +459,10 @@ void nearest_interp(const float* src,
 #pragma omp parallel for collapse(2) schedule(static)
   for (int h = 0; h < h_out; ++h) {
     for (int w = 0; w < w_out; ++w) {
-      int near_x = static_cast<int>(scale_w_new * w + 0.5);
-      int near_y = static_cast<int>(scale_h_new * h + 0.5);
+      int near_x = (with_align) ? static_cast<int>(scale_w_new * w + 0.5)
+                                : static_cast<int>(scale_w_new * w);
+      int near_y = (with_align) ? static_cast<int>(scale_h_new * h + 0.5)
+                                : static_cast<int>(scale_h_new * h);
       near_x = near_x < 0 ? 0 : near_x;
       near_y = near_y < 0 ? 0 : near_y;
       dst[h * w_out + w] = src[near_y * w_in + near_x];

lite/tests/kernels/nearest_interp_compute_test.cc

@@ -51,9 +51,11 @@ void resize_nearest_align(std::vector<const lite::Tensor*> inputs,
       int src_index = n * src_stride_batch + c * src_stride_c;
       for (int h = 0; h < hout; ++h) {
         for (int w = 0; w < wout; ++w) {
-          dtype fw = scale_w * w + 0.5;
+          int fw = (with_align) ? static_cast<int>(scale_w * w + 0.5)
+                                : static_cast<int>(scale_w * w);
           fw = (fw < 0) ? 0 : fw;
-          dtype fh = scale_h * h + 0.5;
+          int fh = (with_align) ? static_cast<int>(scale_h * h + 0.5)
+                                : static_cast<int>(scale_h * h);
           fh = (fh < 0) ? 0 : fh;
           int w_start = static_cast<int>(fw);
           int h_start = static_cast<int>(fh);