Add integration test for deleting struct (#459)

Differentially tests the behavior of deleting a struct with a member
that do not occupy the full 32-byte slot. From [this
issue](https://github.com/paritytech/contract-issues/issues/118) it was
unclear whether the `delete` was expected to reset only the bytes
occupied or the entire slot. The current behavior of resetting the
entire slot is expected.

Cargo.lock

@@ -9154,13 +9154,6 @@ dependencies = [
  "serde",
 ]
 
-[[package]]
-name = "revive-replay"
-version = "0.1.0"
-dependencies = [
- "anyhow",
-]
-
 [[package]]
 name = "revive-runner"
 version = "0.4.0"