Merge #8482: [qa] Use single cache dir for chains

fad8cf6 [qa] Use single cache dir for chains (MarcoFalke)
fa2d68f [qa] Adjust timeouts for micro-optimization of run time (MarcoFalke)
fae596f [qa] Sort scripts by time for pull_tester and don't overwrite setup_chain (MarcoFalke)

qa/rpc-tests/segwit.py

@@ -76,9 +76,10 @@ def find_unspent(node, min_value):
 
 class SegWitTest(BitcoinTestFramework):
 
-    def setup_chain(self):
-        print("Initializing test directory "+self.options.tmpdir)
-        initialize_chain_clean(self.options.tmpdir, 3)
+    def __init__(self):
+        super().__init__()
+        self.setup_clean_chain = True
+        self.num_nodes = 3
 
     def setup_network(self):
         self.nodes = []