Fix dumping codeview line tables when there are multiple debug sections

Codeview line tables for functions in different sections refer to a common
STRING_TABLE_SUBSECTION for filenames.
This happens when building with -Gy or with inline functions with MSVC.

Original patch by Jeff Muizelaar!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219125 91177308-0d34-0410-b5e6-96231b3b80d8