wallet: Add input bytes to CInputCoin

Summary:
With nInputBytes, coin selection can execute without a reference to the COutput

This is a partial backport of Core PR12257 : https://github.com/bitcoin/bitcoin/pull/12257/commits/65b3eda458221644616d0fdd6ba0fe01bdbce893

Test Plan:

make check

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D3391