Exclude RequiresApi from generated stubs

This annotation is required for linting, but is not useful in stubs.

Bug: 185579441
Test: cherry-pick http://ag/14098354 and regenerate stubs
Change-Id: I7e4da99a8843b9c709f3b59f125f43cbd66bda4e
diff --git a/java/droidstubs.go b/java/droidstubs.go
index 2676f3d..90d9896 100644
--- a/java/droidstubs.go
+++ b/java/droidstubs.go
@@ -283,6 +283,8 @@
 	if Bool(d.properties.Annotations_enabled) {
 		cmd.Flag("--include-annotations")
 
+		cmd.FlagWithArg("--exclude-annotation ", "androidx.annotation.RequiresApi")
+
 		validatingNullability :=
 			strings.Contains(String(d.Javadoc.properties.Args), "--validate-nullability-from-merged-stubs") ||
 				String(d.properties.Validate_nullability_from_list) != ""