message: pass import object by reference in some spectests
diff: @@ -99,7 +99,7 @@ pub fn generate_imports() -> ImportObject {
  let module = wasmer_runtime_core::compile_with(&wasm_binary[..], &CraneliftCompiler::new())
  .expect("WASM can't be compiled");
  let instance = module
  - .instantiate(ImportObject::new())
  + .instantiate(&ImportObject::new())
  .expect("WASM can't be instantiated");
  let mut imports = ImportObject::new();
  imports.register("spectest", instance);
  @@ -358,7 +358,7 @@ fn test_module_{}() {{
  println!(\"{{}}\", module_str);
  let wasm_binary = wat2wasm(module_str.as_bytes()).expect(\"WAST not valid or malformed\");
  let module = wasmer_runtime_core::compile_with(&wasm_binary[..], &CraneliftCompiler::new()).expect(\"WASM can't be compiled\");
  - module.instantiate(generate_imports()).expect(\"WASM can't be instantiated\")
  + module.instantiate(&generate_imports()).expect(\"WASM can't be instantiated\")
  }}\n",
  self.last_module,
  // We do this to ident four spaces, so it looks aligned to the function body
  