Column diff indexed access bugs

A recent change expanded how frequently we apply indexedTableAccess, which exposed some brokenness in the `ColumnDiffTable` index access path and overlooked testing. Specifically, we were only lever testing the prepared path, which was not subject to indexed table access.

```diff
@@ -1706,7 +1706,7 @@ func TestColumnDiffSystemTable(t *testing.T) {
}
for _, test := range ColumnDiffSystemTableScriptTests {
t.Run(test.Name, func(t *testing.T) {
- enginetest.TestScriptPrepared(t, newDoltHarness(t), test)
+ enginetest.TestScript(t, newDoltHarness(t), test)
})
}
}
```

Disabling the `sql.IndexAddressable` interface for now, which forces the non-index path.