Update fix for cvtint testbench-fp

Created by: stineje

sim-testfloat-batch failed originally for cvtint. Due to recent changes, the requirement for NaN is no longer required and just goes against TestFloat. Ran tests with "all" tests and they all pass for cvtint. I also tested other tests and they also pass as well. Currently testing more in depth for any issues as always double checking. Left original check in so can see the change - will remove by this weekend.