add another msize test case

Signed-off-by: xermicus <cyrill@parity.io>

crates/llvm-context/src/eravm/evm/context.rs

@@ -201,5 +201,8 @@ where
             .build_ptr_to_int(heap_start, context.xlen_type(), "heap_start")?,
         "heap_size",
     )?;
-    Ok(heap_size.as_basic_value_enum())
+    Ok(context
+        .builder()
+        .build_int_z_extend(heap_size, context.field_type(), "heap_size_extended")?
+        .as_basic_value_enum())
 }

crates/llvm-context/src/eravm/evm/return_data.rs

@@ -89,5 +89,5 @@ where
         "return_data_copy_memcpy_from_return_data",
     )?;
 
-    Ok(())
+    todo!("Build heap GEP to allocate if necessary")
 }