Fix for win32 threads on high end systems

I submitted a patch to LibUV that will fix Julia threading only being able to use 1/2,1/4, or 1/8 of the CPUs on high end windows systems, no matter how many threads you create. Affected systems are any with >64 HW threads (such as 64-core AMD threadrippers), or dual/quad/octa socket systems such as Xeons.