Merge #20023: test: remove unused constants in functional tests

92e28fa test: remove unused constants in functional tests (Sebastian Falbesoner)

Pull request description:

  This mini-PR gets rid of constants in functional tests that are not used anymore. Found by [vulture ](https://pypi.org/project/vulture/)via the following script that has been lying around here locally for quite some time (I think it was once proposed by practicalswift, but I don't remember the concrete topic/PR):
  ```
  #!/bin/sh
  for F in $(git ls-files -- "*.py"); do vulture "$F" | grep "unused variable"; done
  ```

ACKs for top commit:
  practicalswift:
    ACK 92e28fa: patch looks correct.

Tree-SHA512: 16516abc8014207bcefdf0545dffaecff1fbba66f45b54c02371dcfd1f18194855c6b72598c11b5407009561eafe8048d47af3471f0efb1795d52477d5a0232e

test/functional/p2p_segwit.py

@@ -89,7 +89,6 @@
 
 # The versionbit bit used to signal activation of SegWit
 VB_WITNESS_BIT = 1
-VB_PERIOD = 144
 VB_TOP_BITS = 0x20000000
 
 MAX_SIGOP_COST = 80000

test/functional/wallet_multiwallet.py

@@ -21,8 +21,6 @@
     get_rpc_proxy,
 )
 
-FEATURE_LATEST = 169900
-
 got_loading_error = False
 def test_load_unload(node, name):
     global got_loading_error