[ORC] Add UUID support to MachOPlatform::HeaderOptions. (#191873)
MachOPlatform::HeaderOptions now includes an optional UUID field. If
set, this will be used to build an LC_UUID load command for the
JITDylib's MachO header.
No testcase: MachOPlatform construction requires the ORC runtime, which
we can't require in LLVM regression or unit tests. In the future we
should test this through the ORC runtime.