Trace time spent in cp rules for dist targets.

Bug: http://b/259130368
Test: Used patched soong_trace.py to measure this
Change-Id: Ic85e35ad17b18fb316770cdebc3e01f45edfab44
diff --git a/packaging/distdir.mk b/packaging/distdir.mk
index c9508af..153ecf6 100644
--- a/packaging/distdir.mk
+++ b/packaging/distdir.mk
@@ -30,6 +30,7 @@
     $(eval _dist_$$(goal):)))
 
 define copy-one-dist-file
+$(2): .KATI_TAGS += ;rule_name=dist-cp
 $(2): $(1)
 	@echo "Dist: $$@"
 	rm -f $$@