* Changed `memory_grow` and `memory_index` in `Instance` struct to be `pub(crate)` and added the equivalent proxy methods to the `InstanceHandle` struct.
This is the wasmtime-runtime crate, which contains wasm runtime library
support, supporting the wasm ABI used by wasmtime-environ,
wasmtime-jit, and wasmtime-obj.
This crate does not make a host vs. target distinction; it is meant to be compiled for the target.