Tests: Add comment regarding blocked i128 tests

num-traits currently fails to build with i128 feature enabled, even though we have i128 support, since autocfg can't detect it.

Cargo.toml

@@ -51,6 +51,7 @@ float-cmp = "0.8.0"
 [dev-dependencies.num-traits]
 version = "0.2"
 default-features = false
+# features = ["i128"] // Blocked by: https://github.com/rust-num/num-traits/issues/177
 
 [dependencies]
 bitflags = "1.2"

tests/basic_math.rs

@@ -43,6 +43,7 @@ fn subtest() {
 	int_test::<i16>();
 	int_test::<i32>();
 	int_test::<i64>();
+	// int_test::<i128>();  Blocked by https://github.com/rust-num/num-traits/issues/177
 
 	sint_test::<i8>();
 	sint_test::<i16>();