Using both `-principal` and `-short-paths` causes a loop on 4.13

[voodoos]

Given this type definition in a file name main.ml:

type module_declaration_lazy = int

and module_data =
  { mda_declaration : module_declaration_lazy;}

Running:

ocamlmerlin single type-enclosing -position 1:34 -principal -short-paths -filename main.ml < main.ml

Will cause an infinitive loop when using Merlin's 4.13 preview (#1381).

Are necessary to the reproduction:

• Having both flags
• Having the record (a variant is ok)
• Having the recursive type

@ulugbekna @rgrinberg as soon as this is solved we will be able to re-enable the flag in ocaml-lsp

[trefis]

FTR: I reproduced this on Merlin 3.0 and OCaml 4.04. It's still a bug, but shouldn't be considered a blocker for 4.13's release.