Revert "Temporarily disable xhprof profiling, due to stability issues"

This reverts commit 014582e0243e3dfde96be6ce6b7076a3f2360cde.

Change-Id: Ib79c3f295e9e33c5f227ff50e34c1520556450ad
Merge "Revert "Temporarily disable xhprof profiling, due to stability issues""