[llvm-jitlink] Add support for static archives and MachO universal archives.

Archives can now be specified as input files the same way that object
files are. Archives will always be linked after all objects (regardless
of the relative order of the inputs) but before any dynamic libraries or
process symbols.

This patch also relaxes matching for slice triples in
StaticLibraryDefinitionGenerator in order to support this feature:
Vendors need not match if the source vendor is unknown.