Add a Module::deserialize_file method (#3266)

* Add a `Module::deserialize_file` method

This commit adds a new method to the `wasmtime::Module` type,
`deserialize_file`. This is intended to be the same as the `deserialize`
method except for the serialized module is present as an on-disk file.
This enables Wasmtime to internally use `mmap` to avoid copying bytes
around and generally makes loading a module much faster.

A C API is added in this commit as well for various bindings to use this
accelerated path now as well. Another option perhaps for a Rust-based
API is to have an API taking a `File` itself to allow for a custom file
descriptor in one way or another, but for now that's left for a possible
future refactoring if we find a use case.

* Fix compat with main - handle readdonly mmap

* wip

* Try to fix Windows support

crates/c-api/include/wasmtime/module.h

@@ -165,6 +165,26 @@ WASM_API_EXTERN wasmtime_error_t *wasmtime_module_deserialize(
     wasmtime_module_t **ret
 );
 
+/**
+ * \brief Deserialize a module from an on-disk file.
+ *
+ * This function is the same as #wasmtime_module_deserialize except that it
+ * reads the data for the serialized module from the path on disk. This can be
+ * faster than the alternative which may require copying the data around.
+ *
+ * This function does not take ownership of any of its arguments, but the
+ * returned error and module are owned by the caller.
+ *
+ * This function is not safe to receive arbitrary user input. See the Rust
+ * documentation for more information on what inputs are safe to pass in here
+ * (e.g. only that of #wasmtime_module_serialize)
+ */
+WASM_API_EXTERN wasmtime_error_t *wasmtime_module_deserialize_file(
+    wasm_engine_t *engine,
+    const char *path,
+    wasmtime_module_t **ret
+);
+
 #ifdef __cplusplus
 }  // extern "C"
 #endif