swift234

[Driver] Fix references to Clang's profiling runtime.

(1) We no longer put the Clang version string in our copy of or symlink to
    Clang's resource directory.
(2) Newer Clang builds now generate a separate library for the Apple OS
    simulators, instead of a fat binary.

We still need a proper end-to-end test for this, but that depends on
building compiler-rt with Swift, which isn't a standard config yet.