Added automated DNN accuracy test to llvm-lit

hpvm/cmake/TestFile.cmake

hpvm/test/CMakeLists.txt

hpvm/test/dnn_benchmarks/CMakeLists.txt

hpvm/test/dnn_benchmarks/hpvm-c/CMakeLists.txt

hpvm/test/dnn_benchmarks/hpvm-c/check_dnn_acc.py

hpvm/test/dnn_benchmarks/lit.cfg.py

hpvm/test/dnn_benchmarks/lit.site.cfg.py.in

hpvm/test/hpvm_pass/CMakeLists.txt

hpvm/test/hpvm_pass/lit.cfg.py

hpvm/test/hpvm_pass/lit.site.cfg.py.in

hpvm/test/lit.site.cfg.py.in