Merge #18067: wallet: Improve LegacyScriptPubKeyMan::CanProvide script recognition

a304a3632f0437f4d0f04589a2200e2da91624a7 Revert "Store p2sh scripts in AddAndGetDestinationForScript" (Russell Yanofsky)
eb7d8a5b07e89133a5fb465ad1b793362e7439f7 [test] check for addmultisigaddress regression (Sjors Provoost)
005f8a92ccb5bc10c8daa106d75e1c21390461d3 wallet: Improve LegacyScriptPubKeyMan::CanProvide script recognition (Russell Yanofsky)

Pull request description:

  Make `LegacyScriptPubKeyMan::CanProvide` method able to recognize p2sh scripts when the redeem script is present in the `mapScripts` map without the p2sh script also having to be added to the `mapScripts` map. This restores behavior prior to #17261, which I think broke backwards compatibility with old wallet files by no longer treating addresses created by `addmultisigaddress` calls before #17261 as solvable.

  The reason why tests didn't fail with the CanProvide implementation in #17261 is because of a workaround added in 4a7e43e8460127a40a7895519587399feff3b682 "Store p2sh scripts in AddAndGetDestinationForScript", which masked the problem for new `addmultisigaddress` RPC calls without fixing it for multisig addresses already created in old wallet files.

  This change adds a lot of comments and allows reverting commit 4a7e43e8460127a40a7895519587399feff3b682 "Store p2sh scripts in AddAndGetDestinationForScript", so the `AddAndGetDestinationForScript()` function, `CanProvide()` method, and `mapScripts` map should all be more comprehensible

ACKs for top commit:
  Sjors:
    re-ACK a304a3632f0437f4d0f04589a2200e2da91624a7 (rebase, slight text changes and my test)
  achow101:
    re-ACK a304a3632f0437f4d0f04589a2200e2da91624a7
  meshcollider:
    utACK a304a3632f0437f4d0f04589a2200e2da91624a7

Tree-SHA512: 03b625220c49684c376a8062d7646aeba0e5bfe043f977dc7dc357a6754627d594e070e4d458d12d2291888405d94c1dbe08c7787c318374cedd5755e724fb6e

0 files changed, 0 insertions, 0 deletions