Time profiler: small fixes and optimizations
Summary: Fixes from Roman's review here: https://reviews.llvm.org/D58675#1465336
Reviewers: lebedev.ri
Subscribers: hiraditya, mgrang, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D60663
llvm-svn: 358448