fa31ca0c22 qa: Remove redundant checkmempool/checkblockindex extra_args (MarcoFalke)
Pull request description:
They are already enabled by default for regtest:
https://github.com/bitcoin/bitcoin/blob/df9f71274645a917e2578c52a1c59745bce8112d/src/init.cpp#L1002-L1007
Closes #13912. CC #12138
Tree-SHA512: b11a3e8cc4715569f917ab89132f8c8dcae64aebcd7a34182675f86cf7f6e207e3187b7ea01a56c92c8c3af76122b6b995e84f533e134676863f8953dc1f0574
Backport of Core PR13913