* nixos/tests/systemtap: init smoke test
* linuxPackages.systemtap: use --sysroot instead of -r
* nixos/tests/systemtap: rule out warnings
* linuxPackages.systemtap: smaller sysroot
* nixos/tests/systemtap: test on a few more kernels
* linuxPackages.systemtap: provide debuginfo for tracing kernel.function
* linuxPackages.systemtap: test kernel.function probe
* linuxPackages.systemtap: 4.8 -> 5.0a
