tests: restrict feature_segwit legacy wallet import tests

A portion of feature_segwit deals with the legacy wallet IsMine and
import behavior. This is now hidden behind --legacy-wallet

test/functional/feature_segwit.py

@@ -341,6 +341,7 @@ class SegWitTest(BitcoinTestFramework):
         # Mine a block to clear the gbt cache again.
         self.generate(self.nodes[0], 1)
 
+        if not self.options.descriptors:
             self.log.info("Verify behaviour of importaddress and listunspent")
 
             # Some public keys to be used later