Symbolic shape inference: fix a bug in auto_merge when broadcasting (#5349)
The bug happens when merging following shapes:
input0: [1, 1, 'Min(1024, input1_dynamic_axes_3)', 'Min(1024, input1_dynamic_axes_3)']
input1: ['input1_dynamic_axes_1*input1_dynamic_axes_2', 12, 'input1_dynamic_axes_3', 'input1_dynamic_axes_3']
input2: []
The fix is to avoid broadcasting merge on input2