Merge #18561: test: Properly raise FailedToStartError when rpc shutdown before warmup finished

faede1b293 test: Properly raise FailedToStartError when rpc shutdown before warmup finished (MarcoFalke)

Pull request description:

  Should fix issues such as https://travis-ci.org/github/bitcoin/bitcoin/jobs/671910152#L7034

Top commit has no ACKs.

Tree-SHA512: ac659f29c5ec91985c916b734e24911cbf4e2c5c4b1f1891a7e6c2d2511ec285167550fb03848eee4a7a3cbc9f8cdb0c766f4e881d9e44368c7415d007006368

test/functional/test_framework/test_node.py

@@ -233,6 +233,10 @@ class TestNode():
                 # -342 Service unavailable, RPC server started but is shutting down due to error
                 if e.error['code'] != -28 and e.error['code'] != -342:
                     raise  # unknown JSON RPC exception
+            except ConnectionResetError:
+                # This might happen when the RPC server is in warmup, but shut down before the call to getblockcount
+                # succeeds. Try again to properly raise the FailedToStartError
+                pass
             except ValueError as e:  # cookie file not found and no rpcuser or rpcassword. bitcoind still starting
                 if "No RPC credentials" not in str(e):
                     raise