CodeGen: Use LLVM's InstrProfReader in -fprofile-instr-use=

Update clang to use the InstrProfReader from LLVM to read
instrumentation based profile data. This also switches us from the
naive text format to the binary format, since that's what's
implemented in the reader.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@206658 91177308-0d34-0410-b5e6-96231b3b80d8