Remove reference img folder from discovery

This is not used and shouldn't be used since
discovery should not deal with images.

Bug: N/A
Test: existing tests
Change-Id: I6706fda10cfccf23bfa939e0ad0cebc0692236a4
diff --git a/preview/screenshot/preview-screenshot-gradle-plugin/src/main/java/com/android/tools/preview/screenshot/PreviewScreenshotGradlePlugin.kt b/preview/screenshot/preview-screenshot-gradle-plugin/src/main/java/com/android/tools/preview/screenshot/PreviewScreenshotGradlePlugin.kt
index c2ca145..4236d73 100644
--- a/preview/screenshot/preview-screenshot-gradle-plugin/src/main/java/com/android/tools/preview/screenshot/PreviewScreenshotGradlePlugin.kt
+++ b/preview/screenshot/preview-screenshot-gradle-plugin/src/main/java/com/android/tools/preview/screenshot/PreviewScreenshotGradlePlugin.kt
@@ -172,7 +172,6 @@
                             task.previewsOutputFile.set(buildDir.file("$PREVIEW_INTERMEDIATES/$variantSegments/previews_discovered.json"))
                             task.previewsOutputFile.disallowChanges()
                             task.resultsDir.set(buildDir.dir("$PREVIEW_OUTPUT/$variantSegments"))
-                            task.referenceImageDir.set(project.layout.projectDirectory.dir("src/androidTest/screenshot/$variantSegments"))
                             task.analyticsService.set(analyticsServiceProvider)
                             task.usesService(analyticsServiceProvider)
                         }
diff --git a/preview/screenshot/preview-screenshot-gradle-plugin/src/main/java/com/android/tools/preview/screenshot/tasks/PreviewDiscoveryTask.kt b/preview/screenshot/preview-screenshot-gradle-plugin/src/main/java/com/android/tools/preview/screenshot/tasks/PreviewDiscoveryTask.kt
index 76d8230..343e370 100644
--- a/preview/screenshot/preview-screenshot-gradle-plugin/src/main/java/com/android/tools/preview/screenshot/tasks/PreviewDiscoveryTask.kt
+++ b/preview/screenshot/preview-screenshot-gradle-plugin/src/main/java/com/android/tools/preview/screenshot/tasks/PreviewDiscoveryTask.kt
@@ -64,16 +64,12 @@
     @get:OutputDirectory
     abstract val resultsDir: DirectoryProperty
 
-    @get:OutputDirectory
-    abstract val referenceImageDir: DirectoryProperty
-
     @get:Internal
     abstract val analyticsService: Property<AnalyticsService>
 
     @TaskAction
     fun run() = analyticsService.get().recordTaskAction(path) {
         Files.createDirectories(resultsDir.asFile.get().toPath())
-        Files.createDirectories(referenceImageDir.asFile.get().toPath())
 
         val outputFilePath = previewsOutputFile.get().asFile.toPath()
         val classpathJars = mutableListOf<String>()
diff --git a/preview/screenshot/preview-screenshot-gradle-plugin/src/test/java/com/android/tools/preview/screenshot/tasks/PreviewDiscoveryTaskTest.kt b/preview/screenshot/preview-screenshot-gradle-plugin/src/test/java/com/android/tools/preview/screenshot/tasks/PreviewDiscoveryTaskTest.kt
index 105b9b7..6500368 100644
--- a/preview/screenshot/preview-screenshot-gradle-plugin/src/test/java/com/android/tools/preview/screenshot/tasks/PreviewDiscoveryTaskTest.kt
+++ b/preview/screenshot/preview-screenshot-gradle-plugin/src/test/java/com/android/tools/preview/screenshot/tasks/PreviewDiscoveryTaskTest.kt
@@ -44,7 +44,6 @@
         val resultsDir = tempDirRule.newFolder("results")
         val referenceImageDir = tempDirRule.newFolder("references")
         task.resultsDir.set(resultsDir)
-        task.referenceImageDir.set(referenceImageDir)
         task.previewsOutputFile.set(tempDirRule.newFile("previews_discovered.json"))
         task.analyticsService.set(object: AnalyticsService() {
             override val buildServiceRegistry: BuildServiceRegistry = mock(