build/github: quiet bazel output in unit_tests CI job

build/github/unit-tests.sh

@@ -30,8 +30,14 @@ if [ -n "${BASE_SHA:-}" ]; then
   fi
 fi
 
+# Note: --remote_download_minimal is intentionally present despite the warning
+# from bazel about conflict with --remote_download_toplevel (from
+# --config=engflowpublic via engflow-args.sh). Bazel gives explicit command-line
+# flags precedence over config expansions, so 'minimal' is in effect. The warning
+# can be ignored.
 bazel test $TEST_TARGETS //pkg/ui:lint //pkg/ui:test \
     --config crosslinux --jobs 200 --remote_download_minimal \
     --bes_keywords ci-unit-test --config=use_ci_timeouts \
     --build_event_binary_file=bes.bin $(./build/github/engflow-args.sh) \
+    --test_output=summary --test_summary=terse --noshow_progress \
     $EXTRA_PARAMS

pkg/util/metamorphic/constants.go

@@ -11,6 +11,7 @@ import (
 	"os"
 	"strconv"
 	"strings"
+	"testing"
 
 	"github.com/cockroachdb/cockroach/pkg/build/bazel"
 	"github.com/cockroachdb/cockroach/pkg/util/buildutil"
@@ -232,6 +233,19 @@ func metamorphicEligible() bool {
 		return false
 	}
 
+	// Skip when the binary is not a Go test binary. The `crdb_test` build tag
+	// is inherited by non-test binaries built from packages that transitively
+	// import this one — most notably the gomock reflect helpers that rules_go
+	// links and executes at build time to generate mock sources. Those
+	// processes have no reason to randomize constants, and their stderr is
+	// captured into bazel's stdout, producing many "INFO: From
+	// GoMockReflectExecOnlyGen ..." blocks of metamorphic preamble in CI
+	// logs. testing.Testing() is set by a linker-injected var in `go test`
+	// binaries and is safe to read from init().
+	if !testing.Testing() {
+		return false
+	}
+
 	return true
 }