Emit lifetime.start / lifetime.end markers for unnamed temporary objects.

This will give more information to the optimizers so that they can reuse stack slots.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@213576 91177308-0d34-0410-b5e6-96231b3b80d8
Fix build breakage caused by use of std::to_string(int).  Replace with raw_string_ostream.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@213578 91177308-0d34-0410-b5e6-96231b3b80d8
Revert "Emit lifetime.start / lifetime.end markers for unnamed temporary objects."

This commit did break the sanitizer-x86 bot. Revert it while
investigating.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@213579 91177308-0d34-0410-b5e6-96231b3b80d8