Increase trState->totalCost by one with each clear

fdbclient/NativeAPI.actor.cpp

@@ -5816,6 +5816,10 @@ void Transaction::clear(const KeyRangeRef& range, AddConflictRange addConflictRa
 		return;
 
 	t.mutations.emplace_back(req.arena, MutationRef::ClearRange, r.begin, r.end);
+	// NOTE: The throttling cost of each clear is assumed to be one page.
+	// This makes compuation fast, but can be inaccurate and may
+	// underestimate the cost of large clears.
+	++trState->totalCost;
 
 	if (addConflictRange)
 		t.write_conflict_ranges.push_back(req.arena, r);

fdbserver/workloads/TransactionCost.actor.cpp

@@ -115,10 +115,7 @@ class TransactionCostWorkload : public TestWorkload {
 			return Void();
 		}
 
-		int64_t expectedFinalCost() const override {
-			// Clears are not measured in Transaction::getTotalCost
-			return 0;
-		}
+		int64_t expectedFinalCost() const override { return 1; }
 	};
 
 	class ReadRangeTest : public ITest {