Revert of Add GN build rules to allow java_assertion_enabler to enable Java asserts.

third_party/ow2_asm/BUILD.gn

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/rules.gni")
 
 java_prebuilt("asm_java") {
-  # Not "testonly" because //build/android/java_assertion_enabler depends on it.
+  testonly = true
   jar_path = "lib/asm-5.0.1.jar"
 }
 
 java_prebuilt("asm_tree_java") {
   testonly = true
   jar_path = "lib/asm-tree-5.0.1.jar"
   deps = [
     ":asm_java",
   ]
 }
@@ skipping 14 matching lines @@
   ]
 }
 
 java_prebuilt("asm_util_java") {
   testonly = true
   jar_path = "lib/asm-util-5.0.1.jar"
   deps = [
     ":asm_tree_java",
   ]
 }