refine infer shape in box decoder and assign op, test=develop (#19118)

paddle/fluid/operators/detection/box_decoder_and_assign_op.cc

@@ -57,17 +57,19 @@ class BoxDecoderAndAssignOp : public framework::OperatorWithKernel {
                       "The rank of Input of TargetBox must be 2");
     PADDLE_ENFORCE_EQ(box_score_dims.size(), 2,
                       "The rank of Input of BoxScore must be 2");
+    if (ctx->IsRuntime()) {
       PADDLE_ENFORCE_EQ(prior_box_dims[0], target_box_dims[0],
                         "The first dim of prior_box and target_box is roi nums "
                         "and should be same!");
       PADDLE_ENFORCE_EQ(prior_box_dims[0], box_score_dims[0],
                         "The first dim of prior_box and box_score is roi nums "
                         "and should be same!");
-    PADDLE_ENFORCE_EQ(target_box_dims[1], box_score_dims[1] * prior_box_dims[1],
+      PADDLE_ENFORCE_EQ(
+          target_box_dims[1], box_score_dims[1] * prior_box_dims[1],
           "The shape of target_box is [N, classnum * 4], The shape "
           "of box_score is [N, classnum], The shape of prior_box "
           "is [N, 4]");
-
+    }
     ctx->SetOutputDim("DecodeBox", framework::make_ddim({target_box_dims[0],
                                                          target_box_dims[1]}));
     ctx->ShareLoD("TargetBox", /*->*/ "DecodeBox");