BitcodeWriter: WorkList => Worklist, NFC

I have no idea how I chose two different spellings in the space of a
couple of weeks, but now I can't remember what to use where.  Choose
"Worklist".

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266582 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed