Move bulky constants from SobolEngineOpsUtil.h to .cpp file (#37086)
Summary:
Also move statics in global namespace to inlines in `at::native::sobol_utils` namespace
Pull Request resolved: https://github.com/pytorch/pytorch/pull/37086
Test Plan:
CI as well as build with Xcode 11.3
Smoke test perf, compiled using: ` cmake ../pytorch -DPYTHON_EXECUTABLE=/usr/bin/python3.7 -DUSE_CUDA=NO -DBUILD_TEST=YES-DCMAKE_CXX_COMPILER=/usr/bin/cuda-g++ -DCMAKE_C_COMPILER=/usr/bin/cuda-gcc -DUSE_MKLDNN=ON -G Ninja` and run on Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GH running FC-30:
Before:
```
$ python3.7 -m timeit -s 'from torch.quasirandom import SobolEngine; sobol = SobolEngine(65, True, 18)' 'sobol.draw(11)'
50000 loops, best of 5: 7.99 usec per loop
```
After:
```
$ python3.7 -m timeit -s 'from torch.quasirandom import SobolEngine; sobol = SobolEngine(65, True, 18)' 'sobol.draw(11)'
50000 loops, best of 5: 7.72 usec per loop
````
Differential Revision: D21182866
Pulled By: malfet
fbshipit-source-id: d3e501ccb9ffbe6395c1598a6f79f2f2f1f37ee0
