[MoveObjectChecker] handle mark_depends

MoveOnlyBorrowsToDestructure: fix gatherBorrows to ignore mark_dependence base
operand uses.

Author: atrick

lib/SILOptimizer/Mandatory/MoveOnlyBorrowToDestructureUtils.cpp

@@ -1540,6 +1540,12 @@ static bool gatherBorrows(SILValue rootValue,
     // escape. Is it legal to canonicalize ForwardingUnowned?
     case OperandOwnership::ForwardingUnowned:
     case OperandOwnership::PointerEscape:
+      if (auto *md = dyn_cast<MarkDependenceInst>(use->getUser())) {
+        // mark_depenence uses only keep its base value alive; they do not use
+        // the base value itself and are irrelevant for destructuring.
+        if (use == &md->getOperandRef(MarkDependenceInst::Base))
+          continue;
+      }
       return false;
 
     case OperandOwnership::InstantaneousUse: