Use type_contents cache for LSP TypeCoverageRequest
Use type_contents cache for LSP TypeCoverageRequest

Summary: Same as D18739043, but for coverage

Reviewed By: gabelevi

Differential Revision: D18739033

fbshipit-source-id: 3601dc3a3a956038904723165f6a1e697f013a27

facebook/flow,mroch/flow,samwgoldman/flow,facebook/flow,mroch/flow,facebook/flow,facebook/flow,samwgoldman/flow,samwgoldman/flow,mroch/flow,mroch/flow,mroch/flow,mroch/flow,samwgoldman/flow,samwgoldman/flow,mroch/flow,samwgoldman/flow,samwgoldman/flow,facebook/flow,facebook/flow,facebook/flow