test: Set peertimeout in write_config

This avoids having to remember to set it whenever mocktime is used with
peer connections. Also, it might help avoiding disconnects when
attaching a debugger to a running test.

test/functional/feature_bip68_sequence.py

@@ -41,10 +41,7 @@ class BIP68Test(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 2
         self.extra_args = [
-            [
-                "-acceptnonstdtxn=1",
-                "-peertimeout=9999",  # bump because mocktime might cause a disconnect otherwise
-            ],
+            ["-acceptnonstdtxn=1"],
             ["-acceptnonstdtxn=0"],
         ]