Move hiddenapi singleton rules to Soong

Move the rules that build hiddenapi-stubs-flags.txt,
hiddenapi-flags.csv and hiddenapi-greylist.csv into Soong.

Bug: 123645297
Test: m checkbuild
Test: m UNSAFE_DISABLE_HIDDEN_API_FLAGS=true
Change-Id: I90bf58710f6153ee8565994f799d3ec5699bc7fa
diff --git a/java/aar.go b/java/aar.go
index b96f127..b01962a 100644
--- a/java/aar.go
+++ b/java/aar.go
@@ -563,6 +563,10 @@
 	return android.Paths{a.classpathFile}
 }
 
+func (a *AARImport) DexJar() android.Path {
+	return nil
+}
+
 func (a *AARImport) AidlIncludeDirs() android.Paths {
 	return nil
 }