Merge bitcoin#20540: test: Fix wallet_multiwallet issue on windows

fada2df test: Fix wallet_multiwallet issue on windows (MarcoFalke)

Pull request description:

  The error message on windows:

  > 2020-11-30T18:10:47.536032Z ListWalletDir: Error scanning C:\Users\user\AppData\Local\Temp\test_runner_₿_🏃_20201130_181042\wallet_multiwallet_0\node0\regtest\wallets\self_walletdat_symlink: boost::filesystem::status: The name of the file cannot be resolved by the system: "C:\Users\user\AppData\Local\Temp\test_runner_₿_🏃_20201130_181042\wallet_multiwallet_0\node0\regtest\wallets\self_walletdat_symlink\wallet.dat"

ACKs for top commit:
  promag:
    Code review ACK fada2df. Although it could ignore (don't log) directories that lead to no permission error.
  fanquake:
    ACK fada2df

Tree-SHA512: b475162cc3cd1574209d916605b229a79c8089714295f5e16569b71f958f0007d54dc76833938492d931387784588b11b73e3ef00f963540af42c079417f8d72

test/functional/wallet_multiwallet.py

@@ -130,7 +130,7 @@ def wallet_file(name):
         os.mkdir(wallet_dir('no_access'))
         os.chmod(wallet_dir('no_access'), 0)
         try:
-            with self.nodes[0].assert_debug_log(expected_msgs=['Too many levels of symbolic links', 'Error scanning']):
+            with self.nodes[0].assert_debug_log(expected_msgs=['Error scanning']):
                 walletlist = self.nodes[0].listwalletdir()['wallets']
         finally:
             # Need to ensure access is restored for cleanup