[PATCH] math: Add more input to atanh accuracy tests

[Paul Zimmermann]

       Dear Sunil,

> +# the next value generates larger error bounds on x86_64 (binary32)
> +atanh 0x1.f80094p-8

I only find a error of 0.598 ulp, whereas the largest error for binary32
is obtained for 0x1.ec2dd8p-4 (1.73 ulp). More precisely for x=0x1.f80094p-8
glibc 2.35 returns 0x1.f8031ep-8 (x86_64, skylake). Do you get a different value?
Maybe you used different CFLAGS than the default ones?

Best regards,
Paul