Revert "profile: Use a simple binary format for profiling"

This will break without the corresponding change in clang, which I've
reverted until I figure out how to get it to link properly.

This reverts commit r203710.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@203713 91177308-0d34-0410-b5e6-96231b3b80d8