Set testonly to true for targets that depends on base_java_test_support

BUG=640116

Review-Url: https://codereview.chromium.org/2308973002
Cr-Commit-Position: refs/heads/master@{#417144}

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",
@@ -2439,6 +2441,7 @@ if (is_android) {
 
   # GYP: //base.gyp:base_java_unittest_support
   android_library("base_java_unittest_support") {
+    testonly = true
     deps = [
       ":base_java",
     ]

components/invalidation/impl/BUILD.gn

@@ -226,6 +226,7 @@ if (is_android) {
     ]
   }
   android_library("javatests") {
+    testonly = true
     deps = [
       ":java",
       "//base:base_java",

components/precache/android/BUILD.gn

@@ -17,6 +17,7 @@ android_library("precache_java") {
 }
 
 android_library("precache_javatests") {
+  testonly = true
   deps = [
     ":precache_java",
     "//base:base_java_test_support",