Fixing all Makefiles to remove PROMISE backend invocations (now deprecated)

llvm/test/VISC/DNN_Benchmarks/benchmarks/alexnet/Makefile

...SC/DNN_Benchmarks/benchmarks/alexnet/src/alexnet_loop.cpp

llvm/test/VISC/DNN_Benchmarks/benchmarks/alexnet2/Makefile

.../DNN_Benchmarks/benchmarks/alexnet2/src/alexnet2_loop.cpp

.../VISC/DNN_Benchmarks/benchmarks/alexnet_imagenet/Makefile

...benchmarks/alexnet_imagenet/src/alexnet_imagenet_loop.cpp

.../test/VISC/DNN_Benchmarks/benchmarks/lenet_mnist/Makefile

llvm/test/VISC/DNN_Benchmarks/benchmarks/mobilenet/Makefile

llvm/test/VISC/DNN_Benchmarks/benchmarks/resnet18/Makefile

...VISC/DNN_Benchmarks/benchmarks/resnet50_imagenet/Makefile

...est/VISC/DNN_Benchmarks/benchmarks/vgg16_cifar10/Makefile

...marks/benchmarks/vgg16_cifar10/src/vgg16_cifar10_loop.cpp

...st/VISC/DNN_Benchmarks/benchmarks/vgg16_cifar100/Makefile

...arks/benchmarks/vgg16_cifar100/src/vgg16_cifar10_loop.cpp

...st/VISC/DNN_Benchmarks/benchmarks/vgg16_imagenet/Makefile