Fix test generation of numbers

[gprabowski]

Currently in number_test_context.cuh:169 setprecision(3) is used for all number types

effectively if using numbers bigger than 999 this cuts them to 3 significant numbers, not (as probably intended) 3 significant numbers after the dot. This fact is not mentioned anywhere and we couldn't understand why our rounding functor tests were failing without this knowledge.

https://en.cppreference.com/w/cpp/io/manip/setprecision

[gprabowski]

a quick fix would be to change m_max_precision (currently always set to 3) to something more reasonable, like 10 or 19. This fixes our case. Currently tests fail if numbers exceed abs value of 1000 which is important for testing the rounding functor.

[gprabowski]

@abstrackt will make a PR with the suggested fix and link it here when ready