Enable the new PM + SamlePGO + ThinLTO testing.

Summary: This patch should be enabled after https://reviews.llvm.org/D34895

Reviewers: chandlerc, tejohnson, davidxl

Reviewed By: tejohnson

Subscribers: sanjoy, mehdi_amini, inglorion, eraman, cfe-commits

Differential Revision: https://reviews.llvm.org/D34896

llvm-svn: 307438