Do not allow code with warnings to pass CI

.bazelrc

@@ -43,6 +43,7 @@ build --@dawn//src/tint:tint_build_wgsl_writer=True
 # Our dependencies (ICU, zlib, etc.) produce a lot of these warnings, so we disable them. Depending
 # on the clang version, zlib either produces warnings for -Wdeprecated-non-prototype or does not
 # have that option, so disable -Wunknown-warning-option there too.
+build --per_file_copt='external/@-W-no-error'
 build --per_file_copt='external/v8@-Wno-deprecated-declarations'
 build --per_file_copt='external/com_googlesource_chromium_icu@-Wno-ambiguous-reversed-operator,-Wno-deprecated-declarations'
 build --host_per_file_copt='external/com_googlesource_chromium_icu@-Wno-ambiguous-reversed-operator,-Wno-deprecated-declarations'

.github/workflows/test.yml

@@ -167,7 +167,7 @@ jobs:
         # timestamps are no longer being added here, the GitHub logs include timestamps (Use
         # 'Show timestamps' on the web interface)
         run: |
-          bazelisk build --remote_download_minimal ${{ matrix.config.bazel-args }} --jobs=32 --disk_cache=~/bazel-disk-cache --remote_cache=https://bazel:${{ secrets.BAZEL_CACHE_KEY }}@bazel-remote-cache.devprod.cloudflare.dev --verbose_failures --config=v8-codegen-opt //...
+          bazelisk build --remote_download_minimal ${{ matrix.config.bazel-args }} --jobs=32 --disk_cache=~/bazel-disk-cache --remote_cache=https://bazel:${{ secrets.BAZEL_CACHE_KEY }}@bazel-remote-cache.devprod.cloudflare.dev --verbose_failures --copt='-Werror -Wno-error=deprecated-delcarations -Wno-error=#warnings' --config=v8-codegen-opt //...
       - name: Bazel test
         run: |
           bazelisk test --remote_download_minimal ${{ matrix.config.bazel-args }} --jobs=32 --disk_cache=~/bazel-disk-cache --remote_cache=https://bazel:${{ secrets.BAZEL_CACHE_KEY }}@bazel-remote-cache.devprod.cloudflare.dev --keep_going --verbose_failures --test_output=errors --config=v8-codegen-opt //...