This change implements the spec for `ProcessProposal`. It first calls the Tendermint block validation logic to check that all of the proposed block fields are well formed and do not violate any of the rules for Tendermint to consider the block valid and then passes the validated block the `ProcessProposal`.
This change also adds additional fixtures to test the change. It adds the `baseMock` types that holds a mock as well as a reference to `BaseApplication`. If the function was not setup by the test on the contained mock Application, the type delegates to the `BaseApplication` and returns what `BaseApplication` returns.
The change also switches the `makeState` helper to take an arg struct so that an ABCI application can be plumbed through when needed.
closes: #7656