LoopVectorize: Use static function instead of DebugLocSetter class

I used the class to safely reset the state of the builder's debug location.  I
think I have caught all places where we need to set the debug location to a new
one. Therefore, we can replace the class by a function that just sets the debug
location.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185165 91177308-0d34-0410-b5e6-96231b3b80d8
Fix bugpoint execution/reference output file name

sys::fs::unique_file will now loop infinitely if provided with a file name
without '%' characters and the input file already exists. As a result, bugpoint
cannot use a fixed file name for the execution output (including the reference
output).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185166 91177308-0d34-0410-b5e6-96231b3b80d8