ci: apply eight Windows Bazel test jobs in config

.bazelrc

@@ -190,7 +190,7 @@ common:ci-windows-cross --strategy=TestRunner=local
 # V8 embeds IsolateData offsets in snapshot builtins; Windows snapshots must be
 # generated by a Windows mksnapshot binary rather than the Linux RBE host tool.
 common:ci-windows-cross --strategy=V8Mksnapshot=local
-common:ci-windows-cross --local_test_jobs=4
+common:ci-windows-cross --local_test_jobs=8
 common:ci-windows-cross --test_env=RUST_TEST_THREADS=1
 # Native Windows CI still covers the PowerShell parser-process tests. The
 # cross-built gnullvm binaries currently hang in those tests when run on the

.github/workflows/bazel.yml

@@ -225,10 +225,6 @@ jobs:
             --skip_incompatible_explicit_targets
             --test_tag_filters=-argument-comment-lint
             --test_verbose_timeout_warnings
-            # The Windows-cross config caps local test processes at four.
-            # Measure whether the idle host can sustain twice as many test
-            # actions while leaving each Rust harness serialized.
-            --local_test_jobs=8
             # Make every uploaded experiment revision execute its selected
             # tests instead of reusing the prior revision's test action cache.
             --test_env=CODEX_BAZEL_TEST_CACHE_BUST=${GITHUB_SHA}