Extract primary apk from apk set zip

Extract and install the primary apk normally, and then unzip the rest
of them as a post install command.

Bug: 204136549
Test: app_set_test.go
Change-Id: I17437ff27f49df6bc91bdbbea6173b46c7d3ec4e

apex/builder.go

@@ -442,7 +442,8 @@ func (a *apexBundle) buildUnflattenedApex(ctx android.ModuleContext) {
 		} else {
 			if fi.class == appSet {
 				copyCommands = append(copyCommands,
-					fmt.Sprintf("unzip -qDD -d %s %s", destPathDir, fi.builtFile.String()))
+					fmt.Sprintf("unzip -qDD -d %s %s", destPathDir,
+						fi.module.(*java.AndroidAppSet).PackedAdditionalOutputs().String()))
 			} else {
 				copyCommands = append(copyCommands, "cp -f "+fi.builtFile.String()+" "+destPath)
 			}