remove unused import (#13868)

substrate/client/executor/benches/bench.rs

@@ -21,7 +21,7 @@ use codec::Encode;
 
 use sc_executor_common::{
 	runtime_blob::RuntimeBlob,
-	wasm_runtime::{HeapAllocStrategy, WasmInstance, WasmModule, DEFAULT_HEAP_ALLOC_STRATEGY},
+	wasm_runtime::{WasmInstance, WasmModule, DEFAULT_HEAP_ALLOC_STRATEGY},
 };
 use sc_executor_wasmtime::InstantiationStrategy;
 use sc_runtime_test::wasm_binary_unwrap as test_runtime;