message: test(c-api) Fix C warnings.
diff: @@ -212,7 +212,7 @@ mod tests {
  const wasm_externtype_t* extern_type = wasm_exporttype_type(export_type);
  assert(wasm_externtype_kind(extern_type) == WASM_EXTERN_FUNC);
  - wasm_functype_t* func_type = wasm_externtype_as_functype(extern_type);
  + wasm_functype_t* func_type = wasm_externtype_as_functype((wasm_externtype_t*) extern_type);
  const wasm_valtype_vec_t* func_params = wasm_functype_params(func_type);
  assert(func_params->size == 2);
  @@ -230,7 +230,7 @@ mod tests {
  const wasm_externtype_t* extern_type = wasm_exporttype_type(export_type);
  assert(wasm_externtype_kind(extern_type) == WASM_EXTERN_GLOBAL);
  - wasm_globaltype_t* global_type = wasm_externtype_as_globaltype(extern_type);
  + wasm_globaltype_t* global_type = wasm_externtype_as_globaltype((wasm_externtype_t*) extern_type);
  assert(wasm_valtype_kind(wasm_globaltype_content(global_type)) == WASM_I32);
  assert(wasm_globaltype_mutability(global_type) == WASM_CONST);
  }
  @@ -242,7 +242,7 @@ mod tests {
  const wasm_externtype_t* extern_type = wasm_exporttype_type(export_type);
  assert(wasm_externtype_kind(extern_type) == WASM_EXTERN_TABLE);
  - wasm_tabletype_t* table_type = wasm_externtype_as_tabletype(extern_type);
  + wasm_tabletype_t* table_type = wasm_externtype_as_tabletype((wasm_externtype_t*) extern_type);
  assert(wasm_valtype_kind(wasm_tabletype_element(table_type)) == WASM_FUNCREF);
  const wasm_limits_t* table_limits = wasm_tabletype_limits(table_type);
  @@ -257,7 +257,7 @@ mod tests {
  const wasm_externtype_t* extern_type = wasm_exporttype_type(export_type);
  assert(wasm_externtype_kind(extern_type) == WASM_EXTERN_MEMORY);
  - wasm_memorytype_t* memory_type = wasm_externtype_as_memorytype(extern_type);
  + wasm_memorytype_t* memory_type = wasm_externtype_as_memorytype((wasm_externtype_t*) extern_type);
  const wasm_limits_t* memory_limits = wasm_memorytype_limits(memory_type);
  assert(memory_limits->min == 1);
  assert(memory_limits->max == wasm_limits_max_default);
  