InstrProf: Create a PIC version of the profile runtime

These tests were XPASS-ing on Linux bots creating Mach-O, which makes
sense, since the real difference is the object format.

I'm hoping a short-term fix to get these tests passing on ELF is to
create two copies of the runtime -- one built with -fPIC, and one
without.  A follow-up patch will change clang's driver to pick between
them depending on whether `-shared` is specified.