remoteexec_info.bzl: Pass REPROXY_CFG_FILE to the build environment BUG=b:269549907 TEST=CQ Change-Id: I94b073fb9c3c60c95d163da81529c4faea45e2f1 Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/bazel/+/5371385 Tested-by: Ryo Hashimoto <hashimoto@chromium.org> Commit-Queue: Ryo Hashimoto <hashimoto@chromium.org> Reviewed-by: Tim Bain <tbain@google.com>