Add testing/buildbot/tryserver.blink for the GN bots.

testing/buildbot/tryserver.blink

 {
-  "mac_chromium_gn_dbg": {
+  "android_chromium_gn_compile_rel": {
+    "additional_compile_targets": [
+      "chrome_shell_apk"
+    ],
+    "gtest_tests": []
+  },
+  "linux_chromium_gn_rel": {
     "additional_compile_targets": [
       "all"
     ],
-    "gtest_tests": [
-      {
-        "test": "base_unittests"
-      }
-    ]
-  },
-  "mac_chromium_gn_rel": {
-    "additional_compile_targets": [
-      "all"
-    ],
     "gtest_tests": [
       {
         "test": "base_unittests"
       }
     ]
   }
 }