Move cranelift dependencies to wasmtime-environ (#669)

Groups all CL data structures into single dependency to be used accross wasmtime project.

crates/api/src/values.rs

@@ -1,9 +1,9 @@
-use crate::data_structures::ir;
 use crate::externals::Func;
 use crate::r#ref::{AnyRef, HostRef};
 use crate::runtime::Store;
 use crate::types::ValType;
 use std::ptr;
+use wasmtime_environ::ir;
 use wasmtime_jit::RuntimeValue;
 
 #[derive(Debug, Clone)]