Related to PR15589.

llvm-svn: 177891

For iterators where the dereference operator returns by value, LoopConvert
should use 'auto &&' in the range-based for loop expression.

If the dereference operator returns an rvalue reference, this is deemed too
strange and the for loop is not converted.

Moved test case from iterator_failing.cpp to iterator.cpp and added extra
tests.

Fixes PR15437.

Reviewer: gribozavr
llvm-svn: 176631

    
LoopConvert isn't properly handling iterators whose dereference operator
returns by value. This test case demonstrates the failure.

See PR15437.

llvm-svn: 176437

- Turned off -count-only tests as they aren't supported in cpp11-migrate
  yet.
- Updated tests to use new binary name and options to access
  loop-convert transform.
- Fixed header guards to not use restricted names.

Reviewers: klimek, gribozavr
llvm-svn: 171852