Flag --incompatible_no_implicit_file_export will break rules_closure in a future Bazel release

Incompatible flag --incompatible_no_implicit_file_export will be enabled by default in a future Bazel release [1], thus breaking rules_closure.

The flag is documented here: https://github.com/bazelbuild/bazel/issues/10225

Please check the following CI builds for build and test results:

* macOS, OpenJDK 8
* Ubuntu 18.04, OpenJDK 11
* Ubuntu 16.04, OpenJDK 8

Never heard of incompatible flags before? We have [documentation](https://docs.bazel.build/versions/master/backward-compatibility.html) that explains everything.

If you don't want to receive any future issues for rules_closure or if you have any questions,
please file an issue in https://github.com/bazelbuild/continuous-integration

**Important**: Please do NOT modify the issue title since that might break our tools.

[1] The target release hasn't been determined yet. Our tool will update the issue title once the flag flip has been scheduled.

Start by reading Bazel issue 10225 and the backward-compatibility documentation linked in the issue, then inspect the macOS and Ubuntu CI results for the incompatible flag. Determine which rules_closure build or test behavior breaks under --incompatible_no_implicit_file_export; done means the listed CI builds pass with the flag enabled.

Written by the indexing model from the issue text.