Restore a few integration test comments and new-build package arguments.

Some comments were lost in the migration to the new integration test suite.

cabal-testsuite/PackageTests/CustomWithoutCabal/cabal.test.hs

 import Test.Cabal.Prelude
 main = cabalTest $ do
-    r <- fails $ cabal' "new-build" []
+
+    -- This package has explicit setup dependencies that do not include Cabal.
+    -- new-build should try to build it, but configure should fail because
+    -- Setup.hs just prints an error message and exits.
+    r <- fails $ cabal' "new-build" ["custom-setup-without-cabal"]
     assertOutputContains "My custom Setup" r

cabal-testsuite/PackageTests/CustomWithoutCabalDefaultMain/cabal.test.hs

 import Test.Cabal.Prelude
 main = cabalTest $ do
-    r <- fails $ cabal' "new-build" []
+
+    -- This package has explicit setup dependencies that do not include Cabal.
+    -- Compilation should fail because Setup.hs imports Distribution.Simple.
+    r <- fails $ cabal' "new-build" ["custom-setup-without-cabal-defaultMain"]
     assertRegex "Should not have been able to import Cabal"
                 "(Could not find module|Failed to load interface for).*Distribution\\.Simple" r
     {-

cabal-testsuite/PackageTests/Regression/T3436/cabal.test.hs

@@ -4,5 +4,5 @@ main = cabalTest $ do
     -- isn't in the system database and thus we can't see if the
     -- depsolver incorrectly chooses it.  Worth fixing if we figure
     -- out how to simulate the "global" database without root.
-    r <- fails $ cabal' "new-build" ["all"]
+    r <- fails $ cabal' "new-build" ["custom-setup"]
     assertOutputContains "This is Cabal-99999" r

cabal-testsuite/PackageTests/Regression/T3436/sandbox.test.hs

 import Test.Cabal.Prelude
+
+-- Regression test for issue #3436
 main = cabalTest $ do
     withSandbox $ do
         cabal "install" ["./Cabal-99998"]
         cabal_sandbox "add-source" ["Cabal-99999"]
+
+        -- Install custom-setup, which has a setup dependency on Cabal-99999.
+        -- cabal should build the setup script with Cabal-99999, but then
+        -- configure should fail because Setup just prints an error message
+        -- imported from Cabal and exits.
         r <- fails $ cabal' "install" ["custom-setup/"]
         assertOutputContains "This is Cabal-99999" r