test code coverage

[lslusarczyk]

https://clang.llvm.org/docs/SourceBasedCodeCoverage.html or something like this we need to executed both shp and mhp tests so using gcov is probably not an option

We may add this as a separate scan.

But some projects (e.g. botocore using codecov) automatically checks code coverage on commit and rejects if coverage is less than required. It would be great have something like this here.

In that case we need to make gcov/lcov working in shp, which means compiling shp with gcc, then use tutorial how to use codecov with C++ and configure PR check that coverage is good enough.