test: pass datacarriersize option for tests using large outputs (instead of acceptnonstdtxn)

By specifying the `datacarriersize` option instead of the more
generic `acceptnonstdtxn`, we can be more specific about what
part of the transaction is non-standard and can be sure that all
other aspects follow the standard policy.

test/functional/mempool_limit.py

@@ -23,7 +23,7 @@ class MempoolLimitTest(BitcoinTestFramework):
         self.setup_clean_chain = True
         self.num_nodes = 1
         self.extra_args = [[
-            "-acceptnonstdtxn=1",
+            "-datacarriersize=100000",
             "-maxmempool=5",
             "-spendzeroconfchange=0",
         ]]