Remove what looks like dead code in the production of debug lines.

Remove what looks like dead code in the production of debug lines.

We only produce debug line information if we have seen a line directive, so
this code is dead. Also, if we want to be bug by bug compatible with
gas and sometimes produce "empty" .debug_line sections, this will
match the content produced by gas.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118914 91177308-0d34-0410-b5e6-96231b3b80d8