Remove some redundant watchlists.

BUG=NONE

Review URL: https://codereview.chromium.org/1018793003

Cr-Commit-Position: refs/heads/master@{#322458}

WATCHLISTS

@@ -820,8 +820,10 @@
     'android_media': ['avayvod+watch@chromium.org'],
     'android_tab': ['avayvod+watch@chromium.org', 'dtrainor@chromium.org'],
     'android_webview': ['android-webview-reviews@chromium.org'],
-    'app_list': ['tfarina@chromium.org', 'chrome-apps-syd-reviews@chromium.org'],
-    'app_shortcuts': ['chrome-apps-syd-reviews@chromium.org'],
+    'app_list': ['tfarina@chromium.org',
+                 'mgiuca@chromium.org',
+                 'tapted@chromium.org'],
+    'app_shortcuts': ['mgiuca@chromium.org', 'tapted@chromium.org'],
     'appcache': ['michaeln@chromium.org'],
     'apps': ['tfarina@chromium.org', 'chromium-apps-reviews@chromium.org'],
     'ash': ['sadrul@chromium.org',