[DivergenceAnalysis] Separated definition of class into header.

The definition of the DivergenceAnalysis pass was in a CPP
file and wasn't accessible to users of the analysis to get it
through "getAnalysis<>()".
This patch extracts the definition into a separate header that
can be used by users of the analysis to fetch the results.

Patch by Volkan Keles (vkeles@apple.com)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248186 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed