Add core:32 dimension to win_upload_clang

Bug: 731397
Change-Id: Ib834db0c1dbc225cbf1325ce4445a441dd5fe7d4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1529449Reviewed-by: Ryan Tseng <hinoka@chromium.org>
Commit-Queue: Eric Foo <efoo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#642185}

infra/config/cr-buildbucket.cfg

@@ -3490,7 +3490,12 @@ buckets {
     builders { mixins: "win-dawn-try" name: "win-dawn-rel" }
     builders { mixins: "win-try" name: "win_mojo" }
     builders { mixins: "win-optional-gpu-try" name: "win_optional_gpu_tests_rel" }
-    builders { mixins: "win-try" mixins: "upload_clang" name: "win_upload_clang" }
+    builders {
+      mixins: "win-try"
+      mixins: "upload_clang"
+      name: "win_upload_clang"
+      dimensions: "cores:32"
+    }
     builders { mixins: "win-try" name: "win_x64_archive" }
 
     builders {