Fold annotations.

Use annotation slices looked up from map instead of read from disk to
reduce copies.

Bug: 68860345
Bug: 151177513
Bug: 151953481

Test: m all
Test: m systemlicense
Test: m listshare; out/soong/host/linux-x86/bin/listshare ...
Test: m checkshare; out/soong/host/linux-x86/bin/checkshare ...
Test: m dumpgraph; out/soong/host/linux-x86/dumpgraph ...
Test: m dumpresolutions; out/soong/host/linux-x86/dumpresolutions ...

where ... is the path to the .meta_lic file for the system image. In my
case if

$ export PRODUCT=$(realpath $ANDROID_PRODUCT_OUT --relative-to=$PWD)

... can be expressed as:

${PRODUCT}/gen/META/lic_intermediates/${PRODUCT}/system.img.meta_lic

Change-Id: Ibf6f7d319092e0d54ab451ffbbd35dcd7d0080e0
diff --git a/tools/compliance/readgraph.go b/tools/compliance/readgraph.go
index 45fa134..face775 100644
--- a/tools/compliance/readgraph.go
+++ b/tools/compliance/readgraph.go
@@ -188,10 +188,11 @@
 		}
 		annotations := newEdgeAnnotations()
 		for _, a := range ad.Annotations {
-			if len(a) == 0 {
-				continue
+			// look up a common constant annotation string from a small map
+			// instead of creating 1000's of copies of the same 3 strings.
+			if ann, ok := RecognizedAnnotations[a]; ok {
+				annotations.annotations[ann] = true
 			}
-			annotations.annotations[a] = true
 		}
 		*edges = append(*edges, &dependencyEdge{target, dependency, annotations})
 	}