Add a verbose mode to "image dump line-table" and use it to write a .debug_line test

Summary:
The motivation for this is being able to write tests for the upcoming
breakpad line table parser, but this could be useful for testing the
low-level workings of any line table format. Or simply for viewing the
line table information with more detail (the brief format doesn't
include any of the flags for end_of_prologue and similar).

I've also removed the load_addresses argument from the
DumpCompileUnitLineTable function, as it wasn't being used anywhere.

Reviewers: clayborg, zturner

Subscribers: JDevlieghere, lldb-commits

Differential Revision: https://reviews.llvm.org/D56315

llvm-svn: 350802