Provide more `aspects` based on compiler statistics (-Xclang -print-stats)

[ecrypa]

This is just an idea I would like to share with you.

Clang prints several compilation statistics when supplied with the flags -Xclang -print-stats. See this sample output for an empty cpp file. This could be used to provide more aspects for the benchmarks (number of types, more reliable memory footprints(?), ...). I hacked together a clang-only proof of concept for measuring the type count, but I am not planning to continue with it myself. My first measurements of the type count show low-noise data, and there is some correlation with the compilation times.

There should be a way (dump and analyze AST?) to obtain similar statistics from other compilers, too.