DebugInfo: Don't include locations for debug-having code inlined into nodebug functions

This produced 'strange' DWARF anyway - the CU would have no ranges (or
at least not a range including the inlined code) nor any subprogram or
inlined_subroutine - yet the line table would have entries for these
instructions.

(this actually becomes more relevant with changes coming after this,
where a CU without any contents will be omitted entirely - so there
would be no line table to put this on anyway)

llvm-svn: 304004