Support multiple dists per Android.bp module, and dist output selection.

This CL adds "dists" to the base property struct to support multiple
dist file configurations, and generic tag support to dist tagged outputs
of modules.

Fixes: b/152834186
Test: soong tests and `m sdk dist`

Change-Id: I80c86bc9b7b09e671f640a4480c45d438bdd9a2a
Signed-off-by: Jingwen Chen <jingwen@google.com>

android/paths.go

@@ -220,6 +220,15 @@ func (p OptionalPath) String() string {
 // Paths is a slice of Path objects, with helpers to operate on the collection.
 type Paths []Path
 
+func (paths Paths) containsPath(path Path) bool {
+	for _, p := range paths {
+		if p == path {
+			return true
+		}
+	}
+	return false
+}
+
 // PathsForSource returns Paths rooted from SrcDir
 func PathsForSource(ctx PathContext, paths []string) Paths {
 	ret := make(Paths, len(paths))