verify-di: split out VerifierSupport

Split out assertion and output helpers from Verifier in preparation for
writing the DebugInfoVerifier.

<rdar://problem/15500563>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206299 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed