[Android] Generate scripts at build time to run android tests.

components/BUILD.gn

Index: components/BUILD.gn
diff --git a/components/BUILD.gn b/components/BUILD.gn
index 700e862fdf8b42af5a87be903587765d9377c2e5..157fd7914e3b2707d80d5a97ec9a9926d8ca03f4 100644
--- a/components/BUILD.gn
+++ b/components/BUILD.gn
@@ -300,6 +300,11 @@ test("components_unittests") {
     "//ui/base",
     "//ui/resources:ui_test_pak",
   ]
+
+  if (is_android) {
+    isolate_file = "components_unittests.isolate"
+  }
+
   data_deps = [ ":components_tests_pak" ]
 
   if (!is_android && !is_ios) {
@@ -398,8 +403,8 @@ test("components_browsertests") {
       ":components_browsertests_jni_headers",
       "//testing/android/native_test:native_test_util",
     ]
-
     use_launcher = false
+    isolate_file = "components_browsertests.isolate"
   }
 
   if (is_linux) {