Initialize flow var indices
Initialize flow var indices

Initialize the PrimitiveFlowVariable indices to invalid_var_index.

cahaynes/grins,vikramvgarg/grins,nicholasmalaya/grins,vikramvgarg/grins,vikramvgarg/grins,cahaynes/grins,vikramvgarg/grins,cahaynes/grins,vikramvgarg/grins,cahaynes/grins,nicholasmalaya/grins,nicholasmalaya/grins,vikramvgarg/grins,cahaynes/grins,nicholasmalaya/grins,cahaynes/grins