Adding New Sampling Knobs to tensorConvSampSim -- with half interpolation

llvm/projects/hpvm-tensor-rt/autotuner/data/global_knobs.txt

...s/hpvm-tensor-rt/autotuner/tuner_driver_src/benchmarks.py

...tensor-rt/autotuner/tuner_driver_src/run_devtime_tuner.py

...ts/hpvm-tensor-rt/tensor_runtime/src/approx_simulation.cu