Add warning messages for the cases where the inferior process shared cache
differs from lldb's own shared cache, and where the inferior process shared
cache does not match up with the on-disk shared cache file.

Simplify the code where lldb gets its own shared cache uuid a little bit.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@179633 91177308-0d34-0410-b5e6-96231b3b80d8