mb: Add compile targets used by V8 trybot

This unbreaks the V8 Chromium trybot
v8_linux_chromium_gn_rel, broken by missing target mappings
in https://codereview.chromium.org/2352473002

BUG=555273,648153

Review-Url: https://codereview.chromium.org/2350703002
Cr-Commit-Position: refs/heads/master@{#419460}

testing/buildbot/gn_isolate_map.pyl

@@ -703,10 +703,18 @@
     "label": "//ui/ozone/gl:ozone_gl_unittests",
     "type": "console_test_launcher",
   },
+  "pdfium_test": {
+    "label": "//third_party/pdfium/samples:pdfium_test",
+    "type": "additional_compile_target",
+  },
   "peerconnection_unittests": {
     "label": "//webrtc/api:peerconnection_unittests",
     "type": "console_test_launcher",
   },
+  "postmortem-metadata": {
+    "label": "//v8:postmortem-metadata",
+    "type": "additional_compile_target",
+  },
   "ppapi_unittests": {
     "label": "//ppapi:ppapi_unittests",
     "type": "console_test_launcher",

testing/buildbot/tryserver.v8.json

@@ -7,55 +7,13 @@
   },
   "v8_linux_chromium_gn_rel": {
     "additional_compile_targets": [
-      "accessibility_unittests",
-      "aura_unittests",
-      "browser_tests",
-      "cacheinvalidation_unittests",
-      "cast_unittests",
-      "cc_unittests",
-      "chromedriver_unittests",
-      "capture_unittests",
-      "components_browsertests",
-      "components_unittests",
-      "content_browsertests",
-      "content_unittests",
-      "crypto_unittests",
-      "dbus_unittests",
-      "device_unittests",
-      "display_unittests",
-      "events_unittests",
+      "blink_tests",
       "extensions_browsertests",
-      "extensions_unittests",
-      "gcm_unit_tests",
-      "gfx_unittests",
-      "gn_unittests",
-      "google_apis_unittests",
-      "gpu_ipc_service_unittests",
-      "gpu_unittests",
-      "interactive_ui_tests",
-      "ipc_tests",
-      "jingle_unittests",
-      "media_unittests",
-      "media_blink_unittests",
-      "mojo_common_unittests",
-      "mojo_public_bindings_unittests",
-      "mojo_public_system_unittests",
-      "mojo_system_unittests",
-      "nacl_loader_unittests",
+      "gin_unittests",
+      "pdfium_test",
+      "postmortem-metadata",
       "net_unittests",
-      "ppapi_unittests",
-      "printing_unittests",
-      "remoting_unittests",
-      "sandbox_linux_unittests",
-      "skia_unittests",
-      "sql_unittests",
-      "sync_integration_tests",
-      "ui_base_unittests",
-      "ui_touch_selection_unittests",
-      "unit_tests",
-      "url_unittests",
-      "views_unittests",
-      "wm_unittests"
+      "unit_tests"
     ]
   }
 }