[DWARF] Preserve column number when emitting 'line 0' record

Follow-up to r289256, address a FIXME to avoid resetting the column
number. This reduced .debug_line by 2.6% in a RelWithDebInfo
self-build of clang.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289620 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed