Avoid negative values in int64 initialization for cases where int64 parameters…

Avoid negative values in int64 initialization for cases where int64 parameters are used as indices (#3004)

src/tools/nbench/benchmark.cpp

@@ -117,7 +117,7 @@ static void random_init(shared_ptr<runtime::Tensor> tv)
     case element::Type_t::i8: init_int_tv<int8_t>(tv, -1, 1); break;
     case element::Type_t::i16: init_int_tv<int16_t>(tv, -1, 1); break;
     case element::Type_t::i32: init_int_tv<int32_t>(tv, 0, 1); break;
-    case element::Type_t::i64: init_int_tv<int64_t>(tv, -1, 1); break;
+    case element::Type_t::i64: init_int_tv<int64_t>(tv, 0, 1); break;
     case element::Type_t::u8: init_int_tv<uint8_t>(tv, 0, 1); break;
     case element::Type_t::u16: init_int_tv<uint16_t>(tv, 0, 1); break;
     case element::Type_t::u32: init_int_tv<uint32_t>(tv, 0, 1); break;