Misc module/dwarf logging improvements

This change improves the logging for the lldb.module category to note a few interesting cases:

1. Local object file found, but specs not matching
2. Local object file not found, using a placeholder module

The handling and logging for the cases wehre we fail to load compressed dwarf
symbols is also improved.

Differential Revision: https://reviews.llvm.org/D50274

llvm-svn: 339161