Test: Add legacy script edge cases to taproot test #36455

Add feature_taproot spenders for script edge cases that other implementations have gotten wrong: CSV with -2, a 5-byte operand whose value fits in 1 byte, IFDUP on negative or non-minimal zero, ROLL with duplicate values, and OP_16 in a P2SH scriptSig.

Each case hits an already-covered branch, so the minimizer drops it, and none are caught by the current vectors. Naming them lets their dumps be added to the script assets.

These were discovered by finding gaps in an alternate implementation (bitcoin-s)

Script assets: bitcoin-core/qa-assets#297

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External sites

• Code coverage & benchmarks: https://corecheck.dev/bitcoin/bitcoin/pulls/36455
• Ralph review <img src=https://review.fish.foo/assets/bitcoin/bitcoin/36455.png alt="Ralph review status"> https://git.fish.foo/bitcoin/bitcoin/pulls/36455#author-ralph

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