Set testonly to true for targets that depends on base_java_test_support

base/BUILD.gn

Index: base/BUILD.gn
diff --git a/base/BUILD.gn b/base/BUILD.gn
index d37f99bd113c74a283a6bee01ad4c7bb4ce7b2d9..9fb464f661f48227773595b793e34871a3ec2588 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -2327,6 +2327,7 @@ if (is_android) {
 
   # GYP: //base.gyp:base_javatests
   android_library("base_javatests") {
+    testonly = true
     deps = [
       ":base_java",
       ":base_java_test_support",
@@ -2343,6 +2344,7 @@ if (is_android) {
 
   # GYP: //base.gyp:base_java_test_support
   android_library("base_java_test_support") {
+    testonly = true
     deps = [
       ":base_java",
       "//testing/android/reporter:reporter_java",