[FEA] Document Compilation Procedure for Generated PTX Code in UDF Unit Tests

**Is your feature request related to a problem? Please describe.**
Some UDF unit tests include generated PTX code compiled either by Numba or CUDA+NVCC.
A couple of them don't have their source code, compile flags, or compilation process documented, thus, making it difficult to work with for people new to them.

Some of them are:
- https://github.com/rapidsai/cudf/blob/428dc188cab5a51c1e15fb90c93a231ad95b7be2/cpp/tests/streams/binaryop_test.cpp#L96
- https://github.com/rapidsai/cudf/blob/428dc188cab5a51c1e15fb90c93a231ad95b7be2/cpp/tests/jit/parse_ptx_function.cpp#L54
- https://github.com/rapidsai/cudf/blob/428dc188cab5a51c1e15fb90c93a231ad95b7be2/cpp/tests/transform/integration/unary_transform_test.cpp#L79
- https://github.com/rapidsai/cudf/blob/428dc188cab5a51c1e15fb90c93a231ad95b7be2/cpp/tests/streams/transform_test.cpp#L70
- https://github.com/rapidsai/cudf/blob/428dc188cab5a51c1e15fb90c93a231ad95b7be2/cpp/tests/binaryop/binop-generic-ptx-test.cpp#L55
- https://github.com/rapidsai/cudf/blob/428dc188cab5a51c1e15fb90c93a231ad95b7be2/cpp/tests/binaryop/binop-generic-ptx-test.cpp#L55
- https://github.com/rapidsai/cudf/blob/428dc188cab5a51c1e15fb90c93a231ad95b7be2/cpp/tests/rolling/grouped_rolling_test.cpp#L67
- https://github.com/rapidsai/cudf/blob/428dc188cab5a51c1e15fb90c93a231ad95b7be2/cpp/tests/rolling/rolling_test.cpp#L1244
- https://github.com/rapidsai/cudf/blob/428dc188cab5a51c1e15fb90c93a231ad95b7be2/java/src/test/java/ai/rapids/cudf/ColumnVectorTest.java#L67

**Describe the solution you'd like**
For the **full** source code, flags, and environment to be documented. Either in a separate doc and having them referenced in the source code or directly embedded as comments in the source code.