tests: type-expr remove some now useless filtering
tests: type-expr remove some now useless filtering

The test output was unstable because the signature wasn't the same
depending on the backend.
Since we only have one backend, the output is stable.

the-lambda-church/merlin,rgrinberg/merlin,the-lambda-church/merlin,ocaml/merlin,the-lambda-church/merlin,rgrinberg/merlin,rgrinberg/merlin,dra27/merlin,ocaml/merlin,ocaml/merlin,ocaml/merlin,dra27/merlin,dra27/merlin,dra27/merlin,rgrinberg/merlin