Merge #20683: test: Fix restart node race

fab46b34f4 test: Fix restart node race (MarcoFalke)

Pull request description:

  It is not allowed to start a node before it has been fully stopped. Otherwise it could lead to intermittent issues due to access issues (e.g. cookie file https://cirrus-ci.com/task/6409665024098304?command=ci#L4793)

  Fix that by waiting for the node to fully stop.

ACKs for top commit:
  laanwj:
    code review ACK fab46b34f4

Tree-SHA512: 7605cac0573a7b04f05ff110d0131e8940d87f7baf6d698505ed16b363d4d15b1e552c5ffd1a187c8fe5639f7e265c3122734c85283275746e46bd789614fd21

test/functional/test_framework/test_framework.py

@@ -517,13 +517,12 @@ class BitcoinTestFramework(metaclass=BitcoinTestMetaClass):
     def stop_node(self, i, expected_stderr='', wait=0):
         """Stop a bitcoind test node"""
         self.nodes[i].stop_node(expected_stderr, wait=wait)
-        self.nodes[i].wait_until_stopped()
 
     def stop_nodes(self, wait=0):
         """Stop multiple bitcoind test nodes"""
         for node in self.nodes:
             # Issue RPC to stop nodes
-            node.stop_node(wait=wait)
+            node.stop_node(wait=wait, wait_until_stopped=False)
 
         for node in self.nodes:
             # Wait for nodes to stop

test/functional/test_framework/test_node.py

@@ -308,7 +308,7 @@ class TestNode():
     def version_is_at_least(self, ver):
         return self.version is None or self.version >= ver
 
-    def stop_node(self, expected_stderr='', wait=0):
+    def stop_node(self, expected_stderr='', *, wait=0, wait_until_stopped=True):
         """Stop the node."""
         if not self.running:
             return
@@ -337,6 +337,9 @@ class TestNode():
 
         del self.p2ps[:]
 
+        if wait_until_stopped:
+            self.wait_until_stopped()
+
     def is_node_stopped(self):
         """Checks whether the node has stopped.