add Mechine::release_locations_keep_state test

lib/singlepass-backend/src/machine.rs

@@ -419,3 +419,19 @@ impl Machine {
         }
     }
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use dynasmrt::x64::Assembler;
+
+    #[test]
+    fn test_release_locations_keep_state_nopanic() {
+        let mut mechine = Machine::new();
+        let mut assembler = Assembler::new().unwrap();
+        let locs = mechine.acquire_locations(&mut assembler, &[WpType::I32; 10], false);
+
+        mechine.release_locations_keep_state(&mut assembler, &locs);
+    }
+
+}