Replace ModuleContext.AConfig() with Config()

AConfig() now duplicates Config().  Replace the uses of AConfig()
with Config().  Leave AConfig() for now until code in other
projects is cleaned up.

Test: m checkbuild
Change-Id: Ic88be643049d21dba45dbd1a65588ed94bf43bdc
diff --git a/java/builder.go b/java/builder.go
index 4be3b04..be40103 100644
--- a/java/builder.go
+++ b/java/builder.go
@@ -386,7 +386,7 @@
 	dumpDir := android.PathForModuleOut(ctx, "desugar", "classes")
 
 	javaFlags := ""
-	if ctx.AConfig().UseOpenJDK9() {
+	if ctx.Config().UseOpenJDK9() {
 		javaFlags = "--add-opens java.base/java.lang.invoke=ALL-UNNAMED"
 	}