InstrProf: Write raw binary profile from runtime

Write a raw binary profile from the runtime.

<rdar://problem/15950346>
InstrProf: Read raw binary profile in llvm-profdata

Read a raw binary profile that corresponds to a memory dump from the
runtime profile.

The test is a binary file generated from
cfe/trunk/test/Profile/c-general.c with the new compiler-rt runtime and
the matching text version of the input.  It includes instructions on how
to regenerate.

<rdar://problem/15950346>