Merge bitcoin/bitcoin#29500: test: create assert_not_equal util

7bb83f6718 test: create assert_not_equal util and add to where imports are needed (kevkevin)

Pull request description:

  In the functional tests there are lots of cases where we assert != which we now swap with assert_not_equal to be more readable

  This is motivated/uses logic from this PR which was closed https://github.com/bitcoin/bitcoin/pull/28528
  This partially helps https://github.com/bitcoin/bitcoin/issues/23119

  I've broken it up to just `assert_not_equal` to keep the PR smaller as suggested in https://github.com/bitcoin/bitcoin/pull/28528#issuecomment-1959945805

  I can create follow up PR's if this is wanted

ACKs for top commit:
  hodlinator:
    re-ACK 7bb83f6718
  ryanofsky:
    Code review ACK 7bb83f6718. Only change since last review is fixing error message formatting and passing it as a keyword argument
  janb84:
    Re-ACK [7bb83f6](7bb83f6718)

Tree-SHA512: de09f41a690033a5b61e6f861d3bd69a32b889d6655a28fbc0d5cfac9f7ec9c642432967d33913970882b4cfdd47bdd377d0ddc44e25976cbaa49f7f9d8f7b10

test/functional/feature_dbcrash.py

@@ -36,6 +36,7 @@ from test_framework.messages import (
 )
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
+    assert_not_equal,
     assert_equal,
 )
 from test_framework.wallet import (
@@ -274,7 +275,7 @@ class ChainstateWriteCrashTest(BitcoinTestFramework):
         self.log.info(f"Restarted nodes: {self.restart_counts}; crashes on restart: {self.crashed_on_restart}")
 
         # If no nodes were restarted, we didn't test anything.
-        assert self.restart_counts != [0, 0, 0]
+        assert_not_equal(self.restart_counts, [0, 0, 0])
 
         # Make sure we tested the case of crash-during-recovery.
         assert self.crashed_on_restart > 0