cronet: use defaults to enable or disable tests

This is used to disable CtsCronetTestCases in tm-mainline-prod.

Test: TH
Change-Id: Ib789dc592677b16676ad7b9c38f33901569d9db9
diff --git a/Cronet/tests/cts/Android.bp b/Cronet/tests/cts/Android.bp
index 22c4b0e..4a1aa05 100644
--- a/Cronet/tests/cts/Android.bp
+++ b/Cronet/tests/cts/Android.bp
@@ -26,10 +26,28 @@
 // as cronet_test_java_defaults may have different values
 // depending on the branch
 
+java_defaults {
+    name: "CronetTestJavaDefaultsEnabled",
+    enabled: true,
+}
+
+java_defaults {
+    name: "CronetTestJavaDefaultsDisabled",
+    enabled: false,
+}
+
+java_defaults {
+    name: "CronetTestJavaDefaults",
+    defaults: [cronet_test_java_defaults],
+}
+
 android_test {
     name: "CtsCronetTestCases",
     compile_multilib: "both", // Include both the 32 and 64 bit versions
-    defaults: ["cts_defaults"],
+    defaults: [
+        "CronetTestJavaDefaults",
+        "cts_defaults",
+    ],
     sdk_version: "test_current",
     srcs: [
         "src/**/*.java",