Only skip operation on snapshot partitions

On Virtual A/B devices, don't skip SOURCE_COPY on
static partitions.

Test: update_engine_unittest
Test: incremental update to self
Change-Id: I5c93b501e09f50f559151eb77d83052373c90d0d
diff --git a/payload_consumer/delta_performer.cc b/payload_consumer/delta_performer.cc
index 3d38c5b..c49474c 100644
--- a/payload_consumer/delta_performer.cc
+++ b/payload_consumer/delta_performer.cc
@@ -1157,8 +1157,10 @@
   // The device may optimize the SOURCE_COPY operation.
   // Being this a device-specific optimization let DynamicPartitionController
   // decide it the operation should be skipped.
+  const PartitionUpdate& partition = partitions_[current_partition_];
   const auto& partition_control = boot_control_->GetDynamicPartitionControl();
-  bool should_skip = partition_control->ShouldSkipOperation(operation);
+  bool should_skip = partition_control->ShouldSkipOperation(
+      partition.partition_name(), operation);
 
   if (operation.has_src_sha256_hash()) {
     bool read_ok;