Bug 1446791 - Add more windows 10 debug chunks for wpt. r=aryx

--HG--
extra : rebase_source : f3d45209a7d6d9a0afaa28a90ce6ba99f5bb9449

taskcluster/ci/test/web-platform.yml

@@ -29,7 +29,7 @@ web-platform-tests:
             linux.*/debug: 18
             macosx64.*/opt: 8
             macosx64/debug: 16
-            windows10-64-ccov/debug: 15
+            windows10.*/debug: 18
             macosx64-ccov/debug: 24
             default: 12
     max-run-time: