This adds a `--always-lightbeam` option as well as an `--always-cranelift`
option, to allow the compilation strategy to be selected via the
command-line. This also enables regular testing for Lightbeam.
This fixes the memory leaks in the following functions which should not be
returning "owned" pointers:
* `wasm_extern_as_func`
* `wasm_func_as_extern`
* `wasm_extern_as_global`
* `wasm_global_as_extern`
* `wasm_extern_as_memory`
* `wasm_extern_as_table`
Additionally, this commit implements the `wasm_memory_as_extern` and
`wasm_table_as_extern` functions.
Fixes#394.
This commit implements populating the table imports of a module from the API.
It also allows for `anyref` in table types as per the reference types proposal.
This PR fixes the borrow scope of store in the `WrappedCallable` impl of
`WasmTimeFn` such that it does not remain borrowed across the call to
`wasmtime_call_trampoline`. By limiting the scope of the borrow, the
implementation can be reentered if an exported function calls an imported
function, which in turn calls another exported function.
Fixes#365.
