fuzz testing fails for adj and meshex due to length fields

[ScanMountGoat]

Adj and meshex both expose array lengths as fields. The following example fails to read in a write+read+write operation because of the invalid count. The same issue applies to meshex.

Adj {
    entry_count: 4244438268,
    entries: [],
    index_buffer: [
        -772,
        -772,
        -772,
        -772,
        -772,
        -772,
        -772,
    ],
}

• [x] adj
• [ ] meshex

[ScanMountGoat]

One solution is to avoid storing the length fields using BinRead's support for temporary variables. SsbhWrite may require an additional attribute to correctly generate the needed field. An easier option that doesn't rely on macro application order is to simply implement SsbhWrite manually to generate the necessary missing fields.

[ScanMountGoat]

MeshEx tests still fail since the entries and flags can be initialized with a different number of elements. The current implementation returns an error. This could be ignored in the fuzz tests to allow for checking other errors.