[qa] remove root test directory for RPC tests

Github-Pull: #8652
Rebased-From: 438e94dc330a37600ec1d86f2ba8502385b5262d c62cc4ec759a8487373f158b3cbb888efcdd753a

qa/rpc-tests/test_framework/test_framework.py

@@ -123,7 +123,8 @@ class BitcoinTestFramework(object):
         self.add_options(parser)
         (self.options, self.args) = parser.parse_args()
 
-        self.options.tmpdir += '/' + str(self.options.port_seed)
+        # backup dir variable for removal at cleanup
+        self.options.root, self.options.tmpdir = self.options.tmpdir, self.options.tmpdir + '/' + str(self.options.port_seed)
 
         if self.options.trace_rpc:
             logging.basicConfig(level=logging.DEBUG, stream=sys.stdout)
@@ -174,6 +175,8 @@ class BitcoinTestFramework(object):
         if not self.options.nocleanup and not self.options.noshutdown and success:
             print("Cleaning up")
             shutil.rmtree(self.options.tmpdir)
+            if not os.listdir(self.options.root):
+                os.rmdir(self.options.root)
         else:
             print("Not cleaning up dir %s" % self.options.tmpdir)