`ValueMaterializer` is a rewrite of what was called `AdvancedValueInfo`
which follows the same principles.
The main benefits over the old version is:
* We materialize the data-flow graph and the CFG of the relevant part of
root. This makes debugging significantly easier.
* We drop the old MonotoneFramework infrastructure in favor of
getMaximalFixedPoint.
* We significantly reduce the amount of queries we make to
AdvancedValueInfo.
This commit performs the changes necessary in order to integrate with
revng-qa, the new project for cross-project quality assurance.
Basically, the source code of all the tests has been moved in revng-qa,
which will take care of producing "artifacts" (i.e., compiled programs),
using the appropriate cross-compilers.
revng will then consume them and produce new artifacts to be consumed by
other tools down the pipeline.
The directory structure of the tests has been reworked to reflect
`revng-qa`. A large amount of boilerplate code has been dropped.
Note that certain actions, that used to be carried out during testing,
are now part of the regular build process. Specifically, lifting the
tests is performed at build time, so that they can be installed.