CpuMath Enhancement: Accelerate loops in hardware intrinsics implementation

[briancylui]

Style changes needed to solve part of #823

Details

• Make while loops more efficient in src\Microsoft.ML.CpuMath\SseIntrinsics.cs and src\Microsoft.ML.CpuMath\AvxIntrinsics.cs with modified bound checking:

var remainder = count % elementsPerIteration;
float* pEnd = pdst + (count - remainder);
while (pDstCurrent < pEnd)
{ … }

[danmoseley]

@tannergooding is this still relevant? I am not sure where it applies, after #835

[tannergooding]

No, they look like dupes of eachother.