Allow `ArcanistPhutilLibraryLinter` to run with an out-of-date XHPAST binary
Allow `ArcanistPhutilLibraryLinter` to run with an out-of-date XHPAST binary

Summary: There is no need to check if the XHPAST binary is available here because this linter does not actually parse PHP, it only considers the library map.

Test Plan: Removed the XHPAST binary and ran `arc lint` on a bunch of files.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D11528

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