lang/beignet: update to 1.3.1.52 (Release_v1.3 branch snapshot)

Changes: https://github.com/intel/beignet/compare/be0ae74...afd050f6
PR: 217635 218644
Approved by: maintainer timeout (2 months)
MFH: 2017Q2 (requires r437953), 2017Q3 (regression fix for r435144)
Differential Revision: https://reviews.freebsd.org/D11377