By: Tom Sydney Kerckhove <syd@cs-syd.eu>
Use dontInstall instead of a no-op installPhase The coverage and report derivations populate $out directly in buildPhase, so the install phase is unnecessary. Replace the no-op `installPhase = "runHook preInstall; runHook postInstall"` (which only existed to suppress stdenv's default `make install`) with the idiomatic `dontInstall = true`.
| Time to Start | Worker time | Duration | Time to finish | |
| Config | 0s | 7s | 7s | 7s |
| Eval | 7s | 2m31s | 2m31s | 2m39s |
| Build | 1m22s | 5m45s | 1m54s | 3m16s |
| Test | - | - | - | - |
| Deploy | - | - | - | - |
| Suite | 0s | 8m25s | 3m16s | 3m16s |