Merge changes from topics "target-build-unbundled", "unbundled-preopt"

* changes:
  Don't disable dexpreopting implicitly in unbundled builds.
  Add TARGET_BUILD_UNBUNDLED as a variable to control builds.

java/dexpreopt_bootjars.go

@@ -179,15 +179,7 @@ func RegisterDexpreoptBootJarsComponents(ctx android.RegistrationContext) {
 }
 
 func skipDexpreoptBootJars(ctx android.PathContext) bool {
-	if dexpreopt.GetGlobalConfig(ctx).DisablePreopt {
-		return true
-	}
-
-	if ctx.Config().UnbundledBuild() {
-		return true
-	}
-
-	return false
+	return dexpreopt.GetGlobalConfig(ctx).DisablePreopt
 }
 
 type dexpreoptBootJars struct {