tls_generic_test sanitisation.

Note that, for 50 years of Gregorian calendar, you're a few days short.
Rearranging what you have as 6*6*6*400*365*50 and noting that 400 years of Gregorian calendar include 97 leap days, 6*6*6*(400*365 +97)*50 would be the average for 50 years.