Remove cu{blas,sparse,rand,fft} from library checks - #7018

These libraries are not needed by Numba, and pyculib, which used them,
is deprecated / discontinued. There is therefore no point in checking
for these libraries.

Prior to this commit, the library check:

```
$ python -c "from numba import cuda; cuda.cudadrv.libs.test()"
```

gave (for example):

```
Finding cublas from System
	located at /usr/local/cuda/lib64/libcublas.so.11.2.2.29
	trying to open library...	ok
Finding cusparse from System
	located at /usr/local/cuda/lib64/libcusparse.so.11.3.1.29
	trying to open library...	ok
Finding cufft from System
	located at /usr/local/cuda/lib64/libcufft.so.10.4.0.29
	trying to open library...	ok
Finding curand from System
	located at /usr/local/cuda/lib64/libcurand.so.10.2.3.29
	trying to open library...	ok
Finding nvvm from System
	located at /usr/local/cuda/nvvm/lib64/libnvvm.so.4.0.0
	trying to open library...	ok
Finding cudart from System
	located at /usr/local/cuda/lib64/libcudart.so.11.2.29
	trying to open library...	ok
Finding cudadevrt from System
	located at /usr/local/cuda/lib64/libcudadevrt.a
Finding libdevice from System
	searching for compute_20...	ok
	searching for compute_30...	ok
	searching for compute_35...	ok
	searching for compute_50...	ok
```

Now it only prints:

```
Finding nvvm from System
	located at /usr/local/cuda/nvvm/lib64/libnvvm.so.4.0.0
	trying to open library...	ok
Finding cudart from System
	located at /usr/local/cuda/lib64/libcudart.so.11.2.29
	trying to open library...	ok
Finding cudadevrt from System
	located at /usr/local/cuda/lib64/libcudadevrt.a
Finding libdevice from System
	searching for compute_20...	ok
	searching for compute_30...	ok
	searching for compute_35...	ok
	searching for compute_50...	ok
```