Increasing stability of sort in Burg

The state matrix was being generated slightly different
on x86_64 and ARM Linux than on the reference output because
the sort wasn't stable. This new version tries to stabilize
the comparison, but since the structures are big and nested,
there is room for further improvement, if needed.


git-svn-id: https://llvm.org/svn/llvm-project/test-suite/trunk@178547 91177308-0d34-0410-b5e6-96231b3b80d8