Explicitly list testTargets

`testTarget` is a space separated list of test-suites.

We explicitly list all test suites.
This allows us to implement logic in the nixpkgs builder to run test
suites in separate passthru.test derivations.

Author: TeofilC

cabal2nix/src/Distribution/Nixpkgs/Haskell/FromCabal.hs

@@ -112,7 +112,7 @@ fromPackageDescription haskellResolver nixpkgsResolver missingDeps flags Package
     & jailbreak .~ False
     & doCheck .~ True
     & doBenchmark .~ False
-    & testTarget .~ mempty
+    & testTarget .~ unwords (map (unUnqualComponentName . testName) testSuites)
     & hyperlinkSource .~ True
     & enableSplitObjs .~ True
     & enableLibraryProfiling .~ False

cabal2nix/src/Distribution/Nixpkgs/Haskell/FromCabal/PostProcess.hs

@@ -358,7 +358,7 @@ opencvOverrides = set phaseOverrides "hardeningDisable = [ \"bindnow\" ];"
                 . over (libraryDepends . pkgconfig) (replace (pkg "opencv") (pkg "opencv3"))
 
 hspecCoreOverrides :: Derivation -> Derivation   -- https://github.com/hspec/hspec/issues/330
-hspecCoreOverrides = set phaseOverrides "testTarget = \"--test-option=--skip --test-option='Test.Hspec.Core.Runner.hspecResult runs specs in parallel'\";"
+hspecCoreOverrides = set testTarget "--test-option=--skip --test-option='Test.Hspec.Core.Runner.hspecResult runs specs in parallel'"
 
 cabal2nixOverrides :: Derivation -> Derivation
 cabal2nixOverrides = set phaseOverrides $ unlines