[Qbs] QBS script parsing speed

[Jochen Ulrich]

My analysis back then was:

> Well [the time] goes into "Handling Products". So it is ModuleLoader::handleProduct().
> And there, it could be the ModuleMerger. But speculation is dangerous when discussing about performance.
See https://lists.qt-project.org/pipermail/qbs/2019-August/002546.html

You can find my test results together with the scripts to generate the projects here:
https://gist.github.com/j-ulrich/35f345007809c77403a8ee88f4d9db11#file-results-md

Best
Jochen