The error was also reworded to avoid the leading repetition (see expected stderr).

### Reproducers
The test failure can be triggered manually by:
```patch
std::optional<Coin> CCoinsViewErrorCatcher::GetCoin(const COutPoint& outpoint) const
{
-    return ExecuteBackedWrapper<std::optional<Coin>>([&]() { return CCoinsViewBacked::GetCoin(outpoint); }, m_err_callbacks);
+    return CCoinsViewBacked::GetCoin(outpoint);
}
```

### Notes
Note that CCoinsViewErrorCatcher::HaveCoin failure isn't tested since it doesn't seem to be used in production code, all tests pass with:
```patch
bool CCoinsViewErrorCatcher::HaveCoin(const COutPoint& outpoint) const
{
-    return ExecuteBackedWrapper<bool>([&]() { return CCoinsViewBacked::HaveCoin(outpoint); }, m_err_callbacks);
+    throw "CCoinsViewBacked::HaveCoin";
}
```

### Context:

On 64-bit systems, LevelDB uses mmap which reflects file changes immediately.
On 32-bit systems (i686, armhf), mmap is disabled (kDefaultMmapLimit=0 in leveldb/util/env_posix.cc), so LevelDB uses block cache which serves stale data.
The node must be restarted after corruption to clear the cache.

Corruption is placed at the middle to avoid LevelDB's paranoid_checks verification during database open, and -checkblocks=0 -checklevel=0 skips Bitcoin's block verification.

Co-authored-by: MarcoFalke <*~=`'#}+{/-|&$^_@721217.xyz>