Panic in Manager.UnconfirmedParents

[mike76-dev]

UnconfirmedParents panicking when trying to form a V1 contract:

panic: runtime error: index out of range [11] with length 5
goroutine 9302 [running]:
go.sia.tech/coreutils/chain.(*Manager).UnconfirmedParents.func1({0xbe, 0x11, 0x1f, 0x6a, 0xe6, 0x30, 0x10, 0xb7, 0x4b, 0xfd, ...})
         .../go/pkg/mod/go.sia.tech/coreutils@v0.16.1-0.20250607184904-8c78c1233ed4/chain/manager.go:955 +0x1c5
go.sia.tech/coreutils/chain.(*Manager).UnconfirmedParents.func2({{0xc00a11c000, 0x1, 0x1}, {0xc00476e2d0, 0x1, 0x1}, {0xc00477a000, 0x1, 0x1}, {0x0, ...}, ...})
         .../go/pkg/mod/go.sia.tech/coreutils@v0.16.1-0.20250607184904-8c78c1233ed4/chain/manager.go:960 +0x8c
go.sia.tech/coreutils/chain.(*Manager).UnconfirmedParents(_, {{0xc00a11c000, 0x1, 0x1}, {0xc00476e2d0, 0x1, 0x1}, {0xc00477a000, 0x1, 0x1}, ...})
         .../go/pkg/mod/go.sia.tech/coreutils@v0.16.1-0.20250607184904-8c78c1233ed4/chain/manager.go:974 +0x1fd

This happens when I'm running this code:

return append(cm.UnconfirmedParents(txn), txn), nil

[lukechampine]

My gut says this is due to the cached parentMap not being invalidated when it should be. Perhaps we should be setting parentMap = nil in revalidatePool?

[n8maninger]

Fixed by #260