Hadrian: Drop remaining symlink traversal code from build scripts
As previously discussed in https://github.com/snowleopard/hadrian/issues/667,
we do not need the symlink traversal code in build scripts. However, it
appears we forgot to delete this code from our Stack-based build scripts,
which led to placing all build artefacts in an unexpected location when
using Hadrian in combination with symlink trees. This commit fixes this.