Consolidate calls to `ALoc.of_loc` in `statement.ml`
Consolidate calls to `ALoc.of_loc` in `statement.ml`

Summary: I took care to ensure that each `loc` reference here referred to the same `loc` binding, and not a binding which shadowed the main one.

Reviewed By: fishythefish

Differential Revision: D10319628

fbshipit-source-id: a24dec576e14d91b55bf50ca1378a45ca6cf04a2

nmote/flow,nmote/flow,nmote/flow,nmote/flow,nmote/flow,nmote/flow,nmote/flow