[mac/lld] Include archive name in diagnostics

Also, for .o files, include full path as given on link command line.

Before:
    lld: error: undefined symbol [...], referenced from sandbox_logging.o

After:
    lld: error: undefined symbol [...], referenced from libseatbelt.a(sandbox_logging.o)

Move archiveName up to InputFile so we can consistently use toString()
to print InputFiles in diags, and pass it to the ObjFile ctor. This
matches the ELF and COFF ports.

Differential Revision: https://reviews.llvm.org/D92437