Add test case for u128 panic (#5601)

* u128 panic

* Add test case for u128 memory out of bounds error

* Fix check

programs/bpf/rust/128bit/src/lib.rs

@@ -24,6 +24,12 @@ pub extern "C" fn entrypoint(_input: *mut u8) -> bool {
     z -= 1;
     assert_eq!(z, 340_282_366_920_938_463_463_374_607_431_768_211_454);
 
+    // ISSUE: https://github.com/solana-labs/solana/issues/5600
+    // assert_eq!(u128::from(1u32.to_be()), 1);
+
+    // ISSUE: https://github.com/solana-labs/solana/issues/5619
+    // solana_bpf_rust_128bit_dep::two_thirds(10);
+
     let x = u64::max_value();
     assert_eq!(u128::from(x) + u128::from(x), 36_893_488_147_419_103_230);