Add support for firmware/standalone LC_NOTE "main bin spec" corefiles

When a Mach-O corefile has an LC_NOTE "main bin spec" for a
standalone binary / firmware, with only a UUID and no load
address, try to locate the binary and dSYM by UUID and if
found, load it at offset 0 for the user.

Add a test case that tests a firmware/standalone corefile
with both the "kern ver str" and "main bin spec" LC_NOTEs.

<rdar://problem/68193804>

Differential Revision: https://reviews.llvm.org/D88282