rpctest: Cleanup resources on failed setup.

This contains the following upstream commits:
- 5e93b1664e
  - This commit originated from downstream so it is a NOOP
- 0ddd10add6
  - This commit has been reverted since it has already been done.
- fb90c334df

rpcserver_test.go

@@ -118,6 +118,13 @@ func TestMain(m *testing.M) {
 	// purposes.
 	if err := primaryHarness.SetUp(true, 25); err != nil {
 		fmt.Println("unable to setup test chain: ", err)
+
+		// Even though the harness was not fully setup, it still needs
+		// to be torn down to ensure all resources such as temp
+		// directories are cleaned up.  The error is intentionally
+		// ignored since this is already an error path and nothing else
+		// could be done about it anyways.
+		_ = primaryHarness.TearDown()
 		os.Exit(1)
 	}
 

rpctest/rpc_harness_test.go

@@ -441,6 +441,13 @@ func TestMain(m *testing.M) {
 	// 25 mature coinbases to allow spending from for testing purposes.
 	if err = mainHarness.SetUp(true, numMatureOutputs); err != nil {
 		fmt.Println("unable to setup test chain: ", err)
+
+		// Even though the harness was not fully setup, it still needs
+		// to be torn down to ensure all resources such as temp
+		// directories are cleaned up.  The error is intentionally
+		// ignored since this is already an error path and nothing else
+		// could be done about it anyways.
+		_ = mainHarness.TearDown()
 		os.Exit(1)
 	}