[gn build] Add some llvm/tools: llvm-xray, sancov, sanstats, verify-uselistorder, yaml-bench

Also add build file for dependency llvm/lib/XRay.

Needed for check-llvm.

(yaml-bench is an llvm/util, not an llvm/tool.)

Differential Revision: https://reviews.llvm.org/D56163

llvm-svn: 350211