Indicate success for simple options when clang called with -cc1.

Patch by David Wiberg.
[TSan] Fix free_race.c by removing `not` from the test invocation that doesn't fail.
Re-enable check previously disabled due to llvm.org/pr16603
Eliminate CXXConstructorDecl::IsImplicitlyDefined.

This field is just IsDefaulted && !IsDeleted; in all places it's used,
a simple check for isDefaulted() is superior anyway, and we were forgetting
to set it in a few cases.

Also eliminate CXXDestructorDecl::IsImplicitlyDefined, for the same reasons.

No intended functionality change.
clang-format: Fix corner case in OpenMP pragma formatting.

Before:
  #pragma omp reduction( | : var)
After:
  #pragma omp reduction(| : var)
Patch to fix doxygen trailing comments for ObjectiveC methods.
// rdar://14258334
Redirect to the GitHub page (temporary solution).