This reverts commit 1d8c107d49.
After 49e14021be, when using F(-NAN)
instead of -F(NAN) to hide the negation, this test passes correctly.
I hadn't realized that GCC and Clang optimized cos(-x) = cos(x), when
I made 1d8c107d49 (and at the time, the
F() macro didn't work properly with -NAN on all toolchains).