Allow `ArcanistPhutilXHPASTLinter` to be configured from `.arclint`.
Allow `ArcanistPhutilXHPASTLinter` to be configured from `.arclint`.

Summary: Currently, `PhabricatorLintEngine` configures the `ArcanistPhutilXHPASTLinter` linter. In order to use `.arclint` instead, we need to expose the `ArcanistPhutilXHPASTLinter` configuration to the `.arclint` format.

Test Plan: See D9064.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T2039

Differential Revision: https://secure.phabricator.com/D9066

uber/arcanist,Khan/arcanist,codelabs-ch/arcanist,PageUpPeopleOrg/arcanist-patches,memsql/arcanist,r4nt/arcanist,wharris/arcanist,dguo-coursera/arcanist,calblueprint/arcanist,Symplicity/arcanist,Symplicity/arcanist,memsql/arcanist,kevinseelbach/arcanist,sneakpeeq/arcanist,eSpark/arcanist,hach-que/arcanist,chundongwang/arcanist,eSpark/arcanist,sneakpeeq/arcanist,wharris/arcanist,phacility/arcanist,wharris/arcanist,haskell-infra/arcanist,wxstars/arcanist,PageUpPeopleOrg/arcanist-patches,fivestars/arcanist,zhihu/arcanist,r4nt/arcanist,KieranHayes/arcanist,alexmv/arcanist,KieranHayes/arcanist,wikimedia/phabricator-arcanist,zhihu/arcanist,aik099/arcanist,phacility/arcanist,calblueprint/arcanist,Symplicity/arcanist,KieranHayes/arcanist,eSpark/arcanist,hach-que/arcanist,wxstars/arcanist,uber/arcanist,wharris/arcanist,kevinseelbach/arcanist,r4nt/arcanist,fivestars/arcanist,sneakpeeq/arcanist,r4nt/arcanist,aik099/arcanist,fivestars/arcanist,dguo-coursera/arcanist,phacility/arcanist,chundongwang/arcanist,codelabs-ch/arcanist,kevinseelbach/arcanist,PageUpPeopleOrg/arcanist-patches,codelabs-ch/arcanist,sneakpeeq/arcanist,eSpark/arcanist,aik099/arcanist,wikimedia/phabricator-arcanist,wxstars/arcanist,zhihu/arcanist,folsom-labs/arcanist,memsql/arcanist,codelabs-ch/arcanist,folsom-labs/arcanist,folsom-labs/arcanist,Khan/arcanist,phacility/arcanist,aik099/arcanist,calblueprint/arcanist,alexmv/arcanist,coursera/arcanist,KieranHayes/arcanist,coursera/arcanist,codelabs-ch/arcanist,PageUpPeopleOrg/arcanist-patches,jra3/arcanist,wxstars/arcanist,wikimedia/phabricator-arcanist,jra3/arcanist,uber/arcanist,phacility/arcanist,wikimedia/phabricator-arcanist,hach-que/arcanist,uber/arcanist,coursera/arcanist,haskell-infra/arcanist,folsom-labs/arcanist,Symplicity/arcanist,calblueprint/arcanist,chundongwang/arcanist,alexmv/arcanist,haskell-infra/arcanist,fivestars/arcanist,alexmv/arcanist,memsql/arcanist,zhihu/arcanist,chundongwang/arcanist,dguo-coursera/arcanist,jra3/arcanist,dguo-coursera/arcanist,jra3/arcanist,hach-que/arcanist,kevinseelbach/arcanist,Khan/arcanist,Khan/arcanist,coursera/arcanist,haskell-infra/arcanist