4fb3388db9 check that a separator is found for psbt inputs, outputs, and global map (Andrew Chow)
Pull request description:
Currently it doesn't make sure that a separator was found so PSBTs missing a trailing separator would still pass. This fixes that and adds a test case for it.
It really only makes sense to check for the separator for the output maps as if an input or global map was missing a separator, the fields following it would be interpreted as belonging to the previous input or global map. However I have added the check for those two anyways to be consistent.
Tree-SHA512: 50c0c08e201ba02494b369a4d36ddb73e6634eb5a4e4e201c4ef38fd2dbeea2c642b8a04d50c91615da61ecbfade37309e47431368f4b1064539c42015766b50