Flip the default for showing include stacks on notes to false. This

required modifying a few tests that specifically use note include stacks
to check the source manager's view of include stacks. I've simply added
the flag to these tests for now, they may have to be more substantially
changed if we decide to remove support for note include stacks
altogether.

Also, add a test for include stacks on notes that was supposed to go in
with the previous commit.

llvm-svn: 128390