message: Add test for wasm that doesn't export `call`
diff: use casper_types::contracts::DEFAULT_ENTRY_POINT_NAME;
  use parity_wasm::{
  builder,
  - elements::{Instruction, Instructions, Local, ValueType},
  + elements::{Instruction, Instructions, Local, Module, ValueType},
  };
  use casper_engine_test_support::DEFAULT_WASM_CONFIG;
  @@ -110,3 +110,17 @@ pub(crate) fn make_stack_overflow() -> Vec<u8> {
  .build();
  parity_wasm::serialize(module).expect("should serialize")
  }
  +
  +// Prepares a payload that don't export call function
  +pub(crate) fn make_module_without_call() -> Vec<u8> {
  + let module = r#"
  + (module (memory 1)
  + (func (export "i32.add") (param i32 i32) (result i32)
  + get_local 0
  + get_local 0
  + i32.add
  + )
  + )
  + "#;
  + wabt::wat2wasm(module).expect("should parse wat")
  +}
  