Fix CI: arbtest overflow and no-std HashMap lift_map

- component_fuzz: use saturating_sub in generate_hashable_key to prevent
  underflow when fuel is 0 and Enum variant is chosen
- typed: remove incorrect ? operators in lift_map for hashbrown::HashMap
  (with_capacity and insert don't return Result)

Author: yordis

crates/test-util/src/component_fuzz.rs

@@ -227,7 +227,7 @@ impl Type {
             10 => Type::String,
             11 => {
                 let amt = u.int_in_range(1..=(*fuel).max(1).min(257))?;
-                *fuel -= amt;
+                *fuel = fuel.saturating_sub(amt);
                 Type::Enum(amt)
             }
             _ => unreachable!(),

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

@@ -2342,9 +2342,9 @@ where
     K: Lift + Eq + Hash,
     V: Lift,
 {
-    let mut result = HashMap::with_capacity(len)?;
+    let mut result = HashMap::with_capacity(len);
     lift_map_pairs(cx, key_ty, value_ty, ptr, len, |k, v| {
-        result.insert(k, v)?;
+        result.insert(k, v);
         Ok(())
     })?;
     Ok(result)