Merge #15927: [tests] log thread names by default in functional tests

7b29ec277b [tests] Comment for why logging config is set as command-line args. (John Newbery)
ba534ccd56 [tests] log thread names by default in functional tests (John Newbery)

Pull request description:

  More detailed logs are better

ACKs for commit 7b29ec:
  jamesob:
    utACK 7b29ec277b

Tree-SHA512: 327cfedb7b7bf32f7ce1e2de5f70c7092041a8e868e14285a79176277c6cf47ebea27027f68787332f8ad21c7f64d2640dd21813eda5b2bd0e5208a65364a879

test/functional/test_framework/test_node.py

@@ -80,10 +80,14 @@ class TestNode():
         # For those callers that need more flexibility, they can just set the args property directly.
         # Note that common args are set in the config file (see initialize_datadir)
         self.extra_args = extra_args
+        # Configuration for logging is set as command-line args rather than in the bitcoin.conf file.
+        # This means that starting a bitcoind using the temp dir to debug a failed test won't
+        # spam debug.log.
         self.args = [
             self.binary,
             "-datadir=" + self.datadir,
             "-logtimemicros",
+            "-logthreadnames",
             "-debug",
             "-debugexclude=libevent",
             "-debugexclude=leveldb",