Fix erroneous self comparison in KeyValueBackupTaskTest

Bug: 217923092
Test: atest BackupFrameworksServicesRoboTests
Change-Id: I73c88df39b63b40a6ed008c5e7872604a5894fbc
diff --git a/services/Android.bp b/services/Android.bp
index b0a5c66..c8b4969 100644
--- a/services/Android.bp
+++ b/services/Android.bp
@@ -16,6 +16,7 @@
             // "-Xep:AndroidFrameworkBinderIdentity:ERROR",
             "-Xep:AndroidFrameworkCompatChange:ERROR",
             // "-Xep:AndroidFrameworkUid:ERROR",
+            "-Xep:SelfEquals:ERROR",
             // NOTE: only enable to generate local patchfiles
             // "-XepPatchChecks:refaster:frameworks/base/errorprone/refaster/EfficientXml.java.refaster",
             // "-XepPatchLocation:/tmp/refaster/",