[DWARF] Make llvm-dwarfdump display location lists in a .dwp file correctly. Fixes PR38990.

Considers the index when extracting location lists from a .dwp file.
Majority of the patch by David Blaikie.

Reviewers: dblaikie

Differential revision: https://reviews.llvm.org/D53155


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@344807 91177308-0d34-0410-b5e6-96231b3b80d8
8 files changed