Add more integration tests for inlining

[fxamacker]

Updates #292

Add more integration tests for inlining.

For example, inserting a child into a parent, mutating it, removing the child from that parent, mutating it, and then inserting the child into another container, and mutating it.

NOTE: a related issue to add more integration tests will be opened at https://github.com/onflow/cadence

[fxamacker]

See onflow/cadence#2837 and Jan's comment there onflow/cadence#2837 (comment)