Revert "[llvm][ScheduleDAG] SUnit::biasCriticalPath() does not find the critical path consistently (#92368)" (#92992)

This reverts commit f0d1ae8.

This commit breaks tests: http://45.33.8.238/linux/138572/step_11.txt

Author: csstormq

llvm/lib/CodeGen/ScheduleDAG.cpp

@@ -331,10 +331,8 @@ void SUnit::biasCriticalPath() {
   unsigned MaxDepth = BestI->getSUnit()->getDepth();
   for (SUnit::pred_iterator I = std::next(BestI), E = Preds.end(); I != E;
        ++I) {
-    if (I->getKind() == SDep::Data && I->getSUnit()->getDepth() > MaxDepth) {
-      MaxDepth = I->getSUnit()->getDepth();
+    if (I->getKind() == SDep::Data && I->getSUnit()->getDepth() > MaxDepth)
       BestI = I;
-    }
   }
   if (BestI != Preds.begin())
     std::swap(*Preds.begin(), *BestI);