Let's scratch that itch!

In [`src/build.c:1046`](https://github.com/sqlite/sqlite/blob/11e4fdb94861a92e9e14476a8a7cea58d559bb1b/src/build.c#L1046) the parser checks the validity of an object (table, index, view or trigger). If `writable_schema=ON` it skips the error checks in the `CREATE TABLE` statement. Dangerous but convenient. If the schema is corrupt, these checks wouldn't catch it.