[Test] Update bitstream setting example with mode bit overwriting
<openfpga_bitstream_setting>
<pb_type name="clb.fle[arithmetic].soft_adder.adder_lut4" source="eblif" content=".param LUT"/>
+ <pb_type name="clb.fle[arithmetic].soft_adder.adder_lut4" source="eblif" content=".param IN2_IS_CIN" overwrite_mode_bits="true" offset="0"/>
</openfpga_bitstream_setting>
