Adding a few more constraints on the WASM execution environment. Some of these we’re well aware of but others are new constraints to aid performance and scalability.

* Limit initial linear memory size to 16 pages (1MB) maximum
* Limit linear memory initializers to the first page (first 64KB)
* Limit number of table elements to 1024
* Limit mutable globals to a maximum of 1KB
* Limit load/store offsets to a maximum of 1MB (matching maximum runtime size)