fix: returndata merged with child on call frame error

[enitrat]

Pull Request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Build-related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Resolves: #896

What is the new behavior?

• We used to always merge the returndata of a child call frame with its parent frame. Now, we only do it when the child has had an execution success
• Needs to differentiate further between normal reverts (REVERT) and exceptional reverts with feat: differentiate betwteen REVERT opcodes an exceptional failures #897. Only in cases of exceptional reverts should this field NOT be merged with the parent's frame.

Does this introduce a breaking change?

• Yes
• No

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This change is