Implement a pass to merge requantize+dequantize for StableHLO Quantizer
Implement a pass to merge requantize+dequantize for StableHLO Quantizer

This pass will convert req+dq pattern in the quantized fusion to dq+relu(6).

Also add an option in PipelineConfig to enable this pass. This option is defaulted to false for ODML pipeline. But enabled by server.
