Move definition of ModuleMemoryOffset (#3228)

This was historically defined in `wasmtime-environ` but it's only used
in `wasmtime-cranelift`, so this commit moves the definition to the
`debug` module where it's primarily used.

crates/cranelift/src/debug/transform/simulate.rs

@@ -1,6 +1,7 @@
 use super::expression::{CompiledExpression, FunctionFrameInfo};
 use super::utils::{add_internal_types, append_vmctx_info, get_function_frame_info};
 use super::AddressTransform;
+use crate::debug::ModuleMemoryOffset;
 use crate::CompiledFunctions;
 use anyhow::{Context, Error};
 use cranelift_codegen::isa::TargetIsa;
@@ -12,7 +13,7 @@ use std::path::PathBuf;
 use std::sync::atomic::{AtomicUsize, Ordering::SeqCst};
 use wasmparser::Type as WasmType;
 use wasmtime_environ::{
-    DebugInfoData, DefinedFuncIndex, EntityRef, FunctionMetadata, ModuleMemoryOffset, WasmFileInfo,
+    DebugInfoData, DefinedFuncIndex, EntityRef, FunctionMetadata, WasmFileInfo,
 };
 
 const PRODUCER_NAME: &str = "wasmtime";