Merge #14179: qa: Fixups to "Run all tests even if wallet is not compiled"

Summary:
fa8433e379 qa: Remove unneded import_deterministic_coinbase_privkeys overwrite, add comments (MarcoFalke)
e413c2ddd1 qa: Fix codespell error and have lint-spelling error instead of warn (MarcoFalke)

Pull request description:

Currently the functional tests require the wallet module to be compiled into the Bitcoin Core executable. For example the premine (or datadir cache) to speed up tests when run in parallel would mine a bunch of blocks and store the private keys to sign the coinbase tx outputs in a wallet. There is no need to have the overhead of the whole wallet module by using keys that are deterministic for all runs.

Note that this change most likely requires the `./test/cache/` to be cleared.

Tree-SHA512: 9ce26036b0e10f0f888f66a1e50be6a357343f9ffb302ae24a7bb3df2f083a31702ef308b738a03b08a1b623aeddac5d6563dc1b15078c0357b7dafad7808ec3

Backport of Core PR14179

Depends on D5184

Test Plan:

cmake -GNinja .. -DBUILD_BITCOIN_WALLET=OFF
ninja check
ninja check-functional-extended

Reviewers: O1 Bitcoin ABC, #bitcoin_abc, jasonbcox

Reviewed By: O1 Bitcoin ABC, #bitcoin_abc, jasonbcox

Differential Revision: https://reviews.bitcoinabc.org/D5185