[#412] Move `InterpreterTest` to morley-test

Description

Because, historically, nettests had to be placed in their own executable, we had a single component cleveland-nettest where we placed all our nettests.

However, as of !613 (merged), this is no longer the case.

This MR moves the InterpreterTest suite from cleveland-nettest to morley-test, since the suite's purpose is to test the functionality in morley's Michelson.Interpret.

Related issue(s)

Resolves #412 (closed)

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