Fix PSBT error test vectors

Summary: Two of them did fail for various segwit related reasons.

Test Plan: I compiled bitcoin core and ran the test vector through core. Noted the error messages. Then ran the test vector through ABC and figured out the one that failed due to segwit rather than due to what they are supposed to test for. I then updated these test vector accordingly.

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D4454