Add a Component::initialize_copy_on_write_image function

Add a component version of the existing
`Module::initialize_copy_on_write_image` function. For components, this
initializes the copy-on-write images for all contained static modules.
This function is just for optimization purposes, and is not required to
be called.

crates/wasmtime/src/runtime/component/component.rs

@@ -618,6 +618,30 @@ impl Component {
         self.inner.code.code_memory().mmap().image_range()
     }
 
+    /// Force initialization of copy-on-write images to happen here-and-now
+    /// instead of when they're requested during first instantiation.
+    ///
+    /// When [copy-on-write memory
+    /// initialization](crate::Config::memory_init_cow) is enabled then Wasmtime
+    /// will lazily create the initialization image for a component. This method
+    /// can be used to explicitly dictate when this initialization happens.
+    ///
+    /// Note that this largely only matters on Linux when memfd is used.
+    /// Otherwise the copy-on-write image typically comes from disk and in that
+    /// situation the creation of the image is trivial as the image is always
+    /// sourced from disk. On Linux, though, when memfd is used a memfd is
+    /// created and the initialization image is written to it.
+    ///
+    /// Also note that this method is not required to be called, it's available
+    /// as a performance optimization if required but is otherwise handled
+    /// automatically.
+    pub fn initialize_copy_on_write_image(&self) -> Result<()> {
+        for (_, module) in self.inner.static_modules.iter() {
+            module.initialize_copy_on_write_image()?;
+        }
+        Ok(())
+    }
+
     /// Looks up a specific export of this component by `name` optionally nested
     /// within the `instance` provided.
     ///