Remove KEEP from GPUDeviceLostReason Test for next roll

Now that the Chromium change is landed:
https://chromium-review.googlesource.com/c/chromium/src/+/4342174
this should allow the expectation to be automatically removed when the
updated tests are rolled in.
https://github.com/gpuweb/cts/pull/2434

No-Try because only changes a comment.

No-Try: True
Bug: chromium:1424883
Change-Id: I9007aca0df3334264676321b144eb1145a518340
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/124543
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Loko Kung <lokokung@google.com>
Commit-Queue: Kai Ninomiya <kainino@chromium.org>
Auto-Submit: Kai Ninomiya <kainino@chromium.org>
diff --git a/webgpu-cts/expectations.txt b/webgpu-cts/expectations.txt
index 10f0594..52697b9 100644
--- a/webgpu-cts/expectations.txt
+++ b/webgpu-cts/expectations.txt
@@ -513,7 +513,6 @@
 
 ################################################################################
 # GPUDeviceLostReason test needs to be updated for spec change
-# KEEP
 ################################################################################
 crbug.com/1424883 webgpu:api,operation,adapter,requestDevice:invalid: [ Failure ]