build: use directories.add for benchmark androidTest resources

srcDirs(vararg) on AGP 9 source-set Resources is deprecated; switch to
the directories MutableSet API. Preserves the original behavior of
including quartz/src/androidDeviceTest/resources in :benchmark's
androidTest java resources (verified bip39.vectors.json shows up in
processBenchmarkAndroidTestJavaRes output).

benchmark/build.gradle.kts

@@ -28,7 +28,7 @@ android {
 
     sourceSets {
         getByName("androidTest") {
-            resources.srcDirs("../quartz/src/androidDeviceTest/resources")
+            resources.directories.add(file("../quartz/src/androidDeviceTest/resources").path)
         }
     }