Improvements to quantizer: Removed unused qType field, add reshape op (#6179)
* Handle case where bias_name is already quantized
If bias is shared between multiple nodes and we've already quantized it, just return the quantized name from the map
* Remove qType attribute from QuantizedValue and QuantizedInitializer
These are unused (and were incorrectly set in the case of int8 quantization)
* Add Reshape op to quantizer
* Add test for Reshape quant