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/obj/src/data_segment.rs

@@ -1,12 +1,12 @@
 use anyhow::Result;
 use object::write::{Object, StandardSection, Symbol, SymbolSection};
 use object::{SymbolFlags, SymbolKind, SymbolScope};
-use wasmtime_environ::DataInitializer;
+use wasmtime_environ::MemoryInitializer;
 
 /// Declares data segment symbol
 pub fn declare_data_segment(
     obj: &mut Object,
-    _data_initaliazer: &DataInitializer,
+    _memory_initializer: &MemoryInitializer,
     index: usize,
 ) -> Result<()> {
     let name = format!("_memory_{}", index);
@@ -26,12 +26,12 @@ pub fn declare_data_segment(
 /// Emit segment data and initialization location
 pub fn emit_data_segment(
     obj: &mut Object,
-    data_initaliazer: &DataInitializer,
+    memory_initializer: &MemoryInitializer,
     index: usize,
 ) -> Result<()> {
     let name = format!("_memory_{}", index);
     let symbol_id = obj.symbol_id(name.as_bytes()).unwrap();
     let section_id = obj.section_id(StandardSection::Data);
-    obj.add_symbol_data(symbol_id, section_id, data_initaliazer.data, 1);
+    obj.add_symbol_data(symbol_id, section_id, &memory_initializer.data, 1);
     Ok(())
 }