remove four duplicate tests from script_tests.json

Summary:
These are identical to the preceding four test cases.
For the curious: they were introduced like this in 2014 by Peter Todd:
https://github.com/bitcoin/bitcoin/pull/3860

Test Plan: make check

Reviewers: jasonbcox, Fabien, #bitcoin_abc, deadalnix

Reviewed By: jasonbcox, #bitcoin_abc

Differential Revision: https://reviews.bitcoinabc.org/D3237