Fixed a bug with section names containing special characters.

Changed the dwarf aranges code to not use getLabelEndName, as it turns out it's not reliable to call that given user-defined section names. Section names can have characters in that aren't representable as symbol names.

The dwarf-aranges test case has been updated to include a special character, to check this.

This fixes pr17416.

llvm-svn: 191932