This commits adds two passes
- FilterForDecompilationFunctionPass deletes the body of a Function if
it's not a isolated function produced by revng
- FilterForDecompilationModulePass deletes all the bodies of the
functions that are not isolated functions generated by revng
These passes are used at the beginning of the decompilation pipeline, to
prevent all the passes of the decompilation pipeline to run on root and
other big functions coming from QEMU that do not need to be decompiled.
Pietro Fezzardi