IR: Avoid repeating assert condition in Value destructor (#136340)

Author: arsenm

llvm/lib/IR/Value.cpp

@@ -98,9 +98,10 @@ Value::~Value() {
     dbgs() << "While deleting: " << *VTy << " %" << getName() << "\n";
     for (auto *U : users())
       dbgs() << "Use still stuck around after Def is destroyed:" << *U << "\n";
+
+    llvm_unreachable("Uses remain when a value is destroyed!");
   }
 #endif
-  assert(materialized_use_empty() && "Uses remain when a value is destroyed!");
 
   // If this value is named, destroy the name.  This should not be in a symtab
   // at this point.