test: Fail immediately on ErrorResponse

If the server replies with success: false, fail with the error message
rather than hanging blocked waiting for some message to arrive (which it
never will)

Now, the linux failure of RunInTerminal, instead of a hang, looks like:

```
(default):                FAIL (2.58s)
  test/haskell/Test/DAP/Init.hs:163:
  Aborted debugger thread: GHCi.Message.readPipe: end of file

  While handling GHCi.Message.readPipe: end of file

  IPE backtrace:
    GHC.Debugger.Monad. (:)
    GHC.Debugger.Run.debugExecution (haskell-debugger/GHC/Debugger/Run.hs:87:28-35)
    GHC.Debugger.fmap (haskell-debugger/GHC/Debugger/Monad.hs:98:14-20)
    Development.Debug.Adapter.Init.fmap (haskell-debugger/GHC/Debugger/Monad.hs:98:14-20)
    Development.Debug.Adapter.Init.catch (haskell-debugger/GHC/Debugger/Monad.hs:99:26-35)
    Development.Debug.Adapter.Init.debuggerThread (hdb/Development/Debug/Adapter/Init.hs:310:5-8)
    annotateCallStackIO, called at haskell-debugger/GHC/Debugger/Monad.hs:219:104 in haskell-debugger-0.12.3.0-inplace:GHC.Debugger.Monad
    DAP.Adaptor.registerNewDebugSession (src/DAP/Adaptor.hs:181:28-66)
  HasCallStack backtrace:
    collectExceptionAnnotation, called at libraries/ghc-internal/src/GHC/Internal/Exception.hs:170:37 in ghc-internal:GHC.Internal.Exception
    toExceptionWithBacktrace, called at libraries/ghc-internal/src/GHC/Internal/Exception.hs:90:42 in ghc-internal:GHC.Internal.Exception
    throw, called at compiler/GHC/Runtime/Interpreter/Process.hs:133:7 in ghc-9.14.1-8674:GHC.Runtime.Interpreter.Process

  Use -p '/runInTerminal/&&/(default)/' to rerun this test only.
(--internal-interpreter): OK (0.70s)

--- SERVER OUTPUT ---
See: /tmp/nix-shell-90645-1510503319/nix-shell-212288-2997796286/hdb-test-c88ed77b842c68ec/T44
Might need: KEEP_TEMP_DIRS=True
---------------------
```

Where the server output comes from the previous commits which now log
the server stdout/stderr to persistent files if KEEP_TEMP_DIRS=True

Author: alt-romes

test/haskell/Test/DAP/Init.hs

@@ -156,7 +156,12 @@ handleServerTestDAP = do
           case mtxt of
             Just txt -> modifyTVar' clientFullOutput (txt:)
             Nothing  -> pure ()
-      Just "response" -> atomically $ writeTChan clientResponses payload
+      Just "response" ->
+        -- Fail immediately if the server reports failure, even if the test
+        -- is blocked waiting for some other specific message.
+        case parseMaybe parseSuccess payload of
+          Just errMsg -> assertFailure errMsg
+          Nothing     -> atomically $ writeTChan clientResponses payload
       Just "request"  -> atomically $ do writeTChan clientReverseRequests payload
       Just ty      -> assertFailure $ "handleServerTestDAP: Unsupported message type: " ++ show ty
       Nothing      -> assertFailure $ "Received message without type: " ++ show payload
@@ -171,3 +176,12 @@ handleServerTestDAP = do
     parseType = withObject "message" $ \o -> do
       typ <- o .: "type"
       pure ((typ :: String))
+
+    -- Returns an error message when success is False, Nothing when success is True.
+    parseSuccess = withObject "response" $ \o -> do
+      success <- o .: "success"
+      if success
+        then fail "success"
+        else do
+          msg <- o .:? "message" .!= "DAP response had success: false (no message)"
+          pure (msg :: String)