This reverts commit 1f1c0d959da699ce04f7951ecbcdb7976c8c0750.
This doesn't work well with multi-component builds. For example, it requires `"haskell.sessionLoading": "singleComponent"` in VSCode, which makes HLS work less reliably.
The script addition is a bit hacky, but there's no obvious straightforward arch/version-independent way to get most of the build path. And eventually, once issues with HLS etc. are sorted out we will revert to using Cabal hooks anyway.
