The literal NAN in MSVC is a negative NAN, while it is a positive one
in other environments. (strtod("NAN", NULL) did return a positive NAN
though.) In most tests where we test that NANs are preserved, the exact
sign doesn't matter much as long as it matches, but for some tests, it
does matter. Change to using variables with known representation
in the tests where it matters.
Also add a LL suffix to make a tricky constant more correct.
In MSVC, the variable initialization
long long i = -2147483648;
actually sets the variable to the positive value 2147483648 (both
in MSVC 2019 and 2022).
Martin Storsjö
c81a93e86c