CxxUtils: Suppress more undefined behavior warnings.

The ID code in various places contains undefined casts between raw data
containers of PixelCluster+SCT_Cluster to SiCluster (through making
explicit symlinks in SG between them).  There are enough that it's
easiest to just suppress all such warnings involbing PrepRawDataCollection.

Control/CxxUtils/share/ubsan.supp

@@ -2,3 +2,6 @@ vptr_check:sp_counted
 vptr_check:severity_level
 vptr_check:custom_scheduler
 
+# Implicit casts from hard symlinking.
+# PixelCluster, SCT_Cluster -> SiCluster
+vptr_check:PrepRawDataCollection