[lldb] Update crashlog.py to accept multiple results from mdfind

mdfind can return multiple results, some of which are not even dSYM
bundles, but Xcode archives (.xcrachive).

Currently, we end up concatenating the paths, which is obviously bogus.
This patch not only fixes that, but now also skips paths that don't have
a Contents/Resources/DWARF subdirectory.

rdar://81270312

Differential revision: https://reviews.llvm.org/D109263