Make public check_wasm

[loloicci]

compatibility::check_wasm in cosmwasm_vm is needed by cosmwasm-simulator.
So, we make it public.

[loloicci]

We need it for the simulator:

https://github.com/line/cosmwasm/blob/19208d44c124801f22b6ab805813c0b85cb5bd83/packages/vm/src/compatibility.rs#L49-L57

• check wasm memory:
  check the wasm has memory-section and the size of it is valid.
  https://webassembly.github.io/spec/core/binary/modules.html#binary-memsec
• check wasm exports
  check the wasm exports needed endpoints https://github.com/line/cosmwasm/blob/19208d44c124801f22b6ab805813c0b85cb5bd83/packages/vm/src/compatibility.rs#L29-L36
• check wasm imports
  check the wasm imports needed cosmwasm's functions https://github.com/line/cosmwasm/blob/19208d44c124801f22b6ab805813c0b85cb5bd83/packages/vm/src/compatibility.rs#L12-L24
• check wasm features
  check the features the wasm used is a subset of the supported features. https://github.com/line/cosmwasm/blob/19208d44c124801f22b6ab805813c0b85cb5bd83/packages/vm/src/compatibility.rs#L149-L150

[loloicci]

Decide not to export and closed with #87. #87 provides the alternative way to check wasm.