[core] Remove unnecessary code due changes in master in the meantime

core/Cargo.toml

@@ -48,8 +48,8 @@ scale-info = { version = "0.2", default-features = false, features = ["derive"],
 criterion = { version = "0.3", optional = true }
 
 [dev-dependencies]
-quickcheck = "0.9.0"
-quickcheck_macros = "0.8.0"
+quickcheck = "0.9"
+quickcheck_macros = "0.8"
 itertools = "0.9"
 
 [features]

core/src/env/engine/off_chain/test_api.rs

@@ -336,22 +336,6 @@ where
     f(default_accounts)
 }
 
-/// Runs the given closure test function with the default configuration
-/// for the off-chain environment.
-///
-/// Doesn't reuse an off-chain environment which might already exist in
-/// this thread, but instead uses a new off-chain environment instance.
-pub fn run_multiple_tests_in_thread<T, F>(f: F) -> Result<()>
-where
-    T: EnvTypes,
-    F: FnOnce(DefaultAccounts<T>) -> Result<()>,
-    <T as EnvTypes>::AccountId: From<[u8; 32]>,
-{
-    recreate_and_initialize_as_default::<T>()?;
-    let default_accounts = default_accounts::<T>()?;
-    f(default_accounts)
-}
-
 /// Returns the total number of reads and writes of the contract's storage.
 pub fn get_contract_storage_rw<T>(account_id: &T::AccountId) -> Result<(usize, usize)>
 where