Use Tasty for RTS thread count test

This removes test/Makefile since all tests have been moved to be run by
Tasty! Yay!

The thread count is a pretty good example for how the shell is pretty
useful for this kind of tests. DSLs aren't that bad after all...

Makefile

@@ -349,7 +349,6 @@ rts: $(ARCHIVES)
 test:
 	cd compiler && stack test
 	$(MAKE) -C backend test
-	$(MAKE) -C test
 
 test-builtins:
 	cd compiler && stack test --ta '-p "Builtins"'

compiler/test.hs

@@ -142,6 +142,22 @@ rtsTests =
           assertEqual "RTS wthreads error retCode" (ExitFailure 1) returnCode
           assertEqual "RTS wthreads error cmdErr" "ERROR: --rts-wthreads requires an argument.\n" cmdErr
 
+  ,   testCase "thread count" $ do
+          testBuild "" ExitSuccess False "../test/rts/wthreads1.act"
+          (pin, pout, perr, ph) <- runInteractiveProcess "../test/rts/wthreads1" ["--rts-wthreads=7"] Nothing Nothing
+          -- wait for program to start up
+          mpid <- getPid ph
+          case mpid of
+              Just pid -> do
+                  let cmd = "ps -o thcount " ++ show pid
+                  (returnCode, cmdOut, cmdErr) <- readCreateProcessWithExitCode (shell $ cmd) ""
+                  let tCount = read (last $ lines cmdOut)::Int
+                  assertEqual "RTS thread count" 10 tCount
+              Nothing -> do
+                  assertFailure "whtreads1 program should be running"
+          terminateProcess ph
+          waitForProcess ph
+          return ()
   ]
 
 rtsDDBTests =