Remove dead exclude

We removed the generation of old dx tests a long time ago

Bug: b/185205222
Change-Id: I05d270f48d7a109e40b628d7688d1b6158cdbcf0
diff --git a/build.gradle b/build.gradle
index 9ceab6e..e614057 100644
--- a/build.gradle
+++ b/build.gradle
@@ -2303,9 +2303,6 @@
         println "Running with deprecated tool d8, not running any tests"
         include ""
     }
-    if (!project.hasProperty('all_tests')) {
-        exclude "com/android/tools/r8/art/dx/**"
-    }
     if (project.hasProperty('no_arttests')) {
         exclude "com/android/tools/r8/art/**"
     }