Merge bitcoin/bitcoin#22987: qa: Fix "RuntimeError: Event loop is closed" on Windows

357f0c7233 ci: Enable more functional tests on Windows MSVC task (Hennadii Stepanov)
f55932678f qa: Fix "RuntimeError: Event loop is closed" on Windows (Hennadii Stepanov)

Pull request description:

  On master (2161a05855), running functional tests that use the P2P interface ends with an error:
  ```
  RuntimeError: Event loop is closed
  ```

  This PR fixes this bug, and enables more functional tests on Windows MSVC CI task.

  More details about bugfix:
  - [What’s New In Python 3.7](https://docs.python.org/3/whatsnew/3.7.html#asyncio)
  - https://bugs.python.org/issue33792
  - actual [change](https://docs.python.org/3.8/library/asyncio-policy.html#asyncio.WindowsSelectorEventLoopPolicy) done in Python 3.8

  Excluded tests, that are listed in the `EXCLUDE_TESTS` environment variable, need more thorough investigation to be enabled.

ACKs for top commit:
  MarcoFalke:
    review ACK 357f0c7233 🌆

Tree-SHA512: d0ba85be81d55c934959ce7402a9c726598125e9751a1de179d16759d0e8b8a915de879c3a62c12d3564c5e0d9649ebd86963744449626efaa42d9eaa99ad3d0

.cirrus.yml

@@ -75,7 +75,7 @@ task:
     << : *CIRRUS_EPHEMERAL_WORKER_TEMPLATE_ENV
 
 task:
-  name: "Win64 native [unit tests, no functional tests] [msvc]"
+  name: "Win64 native [msvc]"
   << : *FILTER_TEMPLATE
   windows_container:
     cpu: 4
@@ -93,6 +93,7 @@ task:
     QTBASEDIR: 'C:\Qt5.12.11_x64_static_vs2019_160900'
     x64_NATIVE_TOOLS: '"C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\VC\Auxiliary\Build\vcvars64.bat"'
     IgnoreWarnIntDirInTempDetected: 'true'
+    EXCLUDE_TESTS: 'feature_addrman.py,feature_bip68_sequence.py,feature_fee_estimation.py,mining_prioritisetransaction.py,p2p_getaddr_caching.py,p2p_invalid_locator.py,p2p_invalid_tx.py,rpc_misc.py,rpc_net.py,wallet_avoidreuse.py,wallet_descriptor.py,wallet_groups.py,wallet_keypool.py'
   merge_script:
     - git config --global user.email "ci@ci.ci"
     - git config --global user.name "ci"
@@ -146,7 +147,8 @@ task:
     - python test\util\test_runner.py
     - python test\util\rpcauth-test.py
   functional_tests_script:
-    - python test\functional\test_runner.py --ci --quiet --combinedlogslen=4000 --jobs=4 --timeout-factor=8 rpc_help feature_config_args rpc_signer feature_presegwit_node_upgrade "tool_wallet.py --descriptors" --failfast  # TODO enable '--extended' and remove cherry-picked test list
+    # TODO enable '--extended' and drop '--exclude'.
+    - python test\functional\test_runner.py --ci --quiet --combinedlogslen=4000 --jobs=4 --timeout-factor=8 --exclude %EXCLUDE_TESTS% --failfast
 
 task:
   name: 'ARM [unit tests, no functional tests] [bullseye]'

test/functional/test_framework/p2p.py

@@ -577,6 +577,8 @@ class NetworkThread(threading.Thread):
 
         NetworkThread.listeners = {}
         NetworkThread.protos = {}
+        if sys.platform == 'win32':
+            asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
         NetworkThread.network_event_loop = asyncio.new_event_loop()
 
     def run(self):