Document why windows tryjob has stale cancellation turned off

Bug: 1139007
Change-Id: I4307e52114f1cc7a9d18c760014e06e23651708e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2477613
Commit-Queue: Prakhar Asthana <pasthana@google.com>
Reviewed-by: Garrett Beaty <gbeaty@chromium.org>
Auto-Submit: Prakhar Asthana <pasthana@google.com>
Cr-Commit-Position: refs/heads/master@{#818953}

infra/config/subprojects/chromium/try.star

@@ -1443,6 +1443,9 @@ try_.chromium_win_builder(
     ssd = True,
     use_clang_coverage = True,
     main_list_view = "try",
+    # TODO(https://crbug/1127113): Recipe Engine doesn't handle cancellations
+    # of stale tryjobs gracefully, resulting in longer average build times.
+    # Windows is particularly susceptible to this.
     tryjob = try_.job(cancel_stale = False),
 )