[DomTree] verifyDomTree to unconditionally perform DT verification

I folded the check for the flag -verify-dom-info into the only caller
where I think it is supposed to be checked: verifyAnalysis.  (The idea
of the flag is to enable this expensive verification in
verifyPreservedAnalysis.)

I'm assuming that when manually scheduling the verification pass
with -passes=verify<domtree>, we do want to perform the verification.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236575 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Scalar/PlaceSafepoints.cpp

@@ -455,10 +455,9 @@ static Instruction *findLocationForEntrySafepoint(Function &F,
   // Note: SplitBlock modifies the DT.  Simply passing a Pass (which is a
   // module pass) is not enough.
   DT.recalculate(F);
-#ifndef NDEBUG
+
   // SplitBlock updates the DT
-  DT.verifyDomTree();
-#endif
+  DEBUG(DT.verifyDomTree());
 
   return BB->getTerminator();
 }