Code review feedback changes.

* Add `anyhow` dependency to `wasmtime-runtime`.
* Revert `get_data` back to `fn`.
* Remove `DataInitializer` and box the data in `Module` translation instead.
* Improve comments on `MemoryInitialization`.
* Remove `MemoryInitialization::OutOfBounds` in favor of proper bulk memory
  semantics.
* Use segmented memory initialization except for when the uffd feature is
  enabled on Linux.
* Validate modules with the allocator after translation.
* Updated various functions in the runtime to return `anyhow::Result`.
* Use a slice when copying pages instead of `ptr::copy_nonoverlapping`.
* Remove unnecessary casts in `OnDemandAllocator::deallocate`.
* Better document the `uffd` feature.
* Use WebAssembly page-sized pages in the paged initialization.
* Remove the stack pool from the uffd handler and simply protect just the guard
  pages.

crates/runtime/src/instance.rs

@@ -834,12 +834,12 @@ impl Instance {
     ///
     /// Resetting the guard pages is required before growing memory.
     #[cfg(all(feature = "uffd", target_os = "linux"))]
-    pub(crate) fn reset_guard_pages(&self) -> Result<(), String> {
+    pub(crate) fn reset_guard_pages(&self) -> anyhow::Result<()> {
         let mut faults = self.guard_page_faults.borrow_mut();
         for (addr, len, reset) in faults.drain(..) {
             unsafe {
                 if !reset(addr, len) {
-                    return Err("failed to reset previously faulted memory guard page".into());
+                    anyhow::bail!("failed to reset previously faulted memory guard page");
                 }
             }
         }