[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 1f19490067cfcf18a9bb0ef29080c1d27cc2f1ec..12c8a510d6ed38ffcac60eaec4e1697f8f0dffbe 100644
--- a/components/BUILD.gn
+++ b/components/BUILD.gn
@@ -299,6 +299,11 @@ test("components_unittests") {
     "//net",
     "//ui/base",
   ]
+
+  if (is_android) {
+    isolate_file = "components_unittests.isolate"
+  }
+
   data_deps = [ ":components_tests_pak" ]
 
   if (!is_android && !is_ios) {
@@ -403,8 +408,8 @@ 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) {