fix(napi) use c_char instead of hardcoding i8 to avoid incompatibilit…

…y with aarch64 (denoland#17458)

Quick one, compatibility fix for [aarch64
builds](https://github.com/LukeChannings/deno-arm64).

test_napi/src/typedarray.rs

@@ -9,6 +9,7 @@ use napi_sys::TypedarrayType;
 use napi_sys::ValueType::napi_number;
 use napi_sys::ValueType::napi_object;
 use napi_sys::*;
+use std::os::raw::c_char;
 use std::ptr;
 
 extern "C" fn test_multiply(
@@ -103,7 +104,8 @@ extern "C" fn test_multiply(
  assert_napi_ok!(napi_throw_error(
  env,
  ptr::null(),
- "Typed array was of a type not expected by test.".as_ptr() as *const i8,
+ "Typed array was of a type not expected by test.".as_ptr()
+ as *const c_char,
  ));
  return ptr::null_mut();
  }