fuzz: improve scriptpubkeyman target

[brunoerg]

Fixes #30541

This PR aims to improve scriptpubkeyman target to avoid timeouts. The input provided in #30541 takes too much time to run because it basically calls only MarkUnusedAddresses (300 times * number of spks). The following changes were made to improve it:

• Reduce keypool size.
• When calling MarkUnusedAddresses, do it with one of the spks per iteration.
• Remove the specific AddDescriptorKey call since it is already covered with AddWalletDescriptor.
• Limit number of iterations to a reasonable value.

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Type	Reviewers
ACK	maflcko, achow101

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Conflicts

Reviewers, this pull request conflicts with the following ones:

• #30221 (wallet: Ensure best block matches wallet scan state by achow101)
• #28333 (wallet: Construct ScriptPubKeyMans with all data rather than loaded progressively by achow101)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

[brunoerg]

cc: @maflcko

[maflcko]

calls only MarkUnusedAddresses (300 times * number of spks)

Are they different spks? IIRC when I looked, they looked all identical, which I am not sure is working as intended.

[brunoerg]

Are they different spks? IIRC when I looked, they looked all identical, which I am not sure is working as intended.

For that input, it was calling MarkUnusedAddresses with all spks every iteration. Besides that, every time MarkUnusedAddresses is called, the number of spks increases. That's why it takes a lot time to run.

Now, it will just call MarkUnusedAddresses with just one spk (randomly) per iteration. Besides that, the number of iterations was reduced for a reasonable value.

[maflcko]

lgtm ACK fd7cd3b8b24ad86dae5c16addbb5acafa18efc0a

[brunoerg]

Force-pushed addressing #30563 (comment)

[maflcko]

lgtm ACK 401cc4e

[achow101]

ACK 401cc4e