Remove link_chrome_on_windows GN flag.

This flag was used to disable linking when the bots were too behind. It's not needed any more.

Review URL: https://codereview.chromium.org/974543002

Cr-Commit-Position: refs/heads/master@{#318795}
diff --git a/extensions/shell/BUILD.gn b/extensions/shell/BUILD.gn
index 70aef27..2e12978 100644
--- a/extensions/shell/BUILD.gn
+++ b/extensions/shell/BUILD.gn
@@ -127,7 +127,7 @@
   }
 }
 
-if (!(is_chromeos && !use_ozone) && (!is_win || link_chrome_on_windows)) {
+if (!(is_chromeos && !use_ozone)) {
   executable("app_shell") {
     # testonly because :app_shell_lib is testonly. See :app_shell_lib comment.
     testonly = true