Make AsmPrinter::EmitLabelOffsetDifference a static helper and simplify.

It had exactly one caller in a position where we know hasSetDirective is true.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220250 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed