WebGPU CTS: Increase timeout with ASAN and backend validation

These tests usually run with a timeout of 12000ms. Increase it
when running on ASAN or backend validation to account for the
additional test overhead.

Bug: 1208253
Change-Id: I4bc13e6c49e056f15eecadb7da5dbaba59f582a0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3038877
Commit-Queue: Austin Eng <[email protected]>
Reviewed-by: Kai Ninomiya <[email protected]>
Reviewed-by: Kenneth Russell <[email protected]>
Cr-Commit-Position: refs/heads/master@{#903250}
diff --git a/testing/buildbot/test_suite_exceptions.pyl b/testing/buildbot/test_suite_exceptions.pyl
index d65cffd2..47b0a7b 100644
--- a/testing/buildbot/test_suite_exceptions.pyl
+++ b/testing/buildbot/test_suite_exceptions.pyl
@@ -3178,6 +3178,16 @@
       },
     },
   },
+  'webgpu_blink_web_tests': {
+    'modifications': {
+      # Increase the timeout with ASAN (crbug.com/1208253)
+      'Dawn Win10 x64 ASAN Release': {
+        'args': [
+          '--time-out-ms=48000',
+        ],
+      },
+    },
+  },
   'webkit_unit_tests': {
     'remove_from': [
       # Flakily fails on Win7. https://crbug.com/943372.