Bazel: Make build tool chain forward compatible
Bazel: Make build tool chain forward compatible

Bazel 0.27 is going to flip incompatible Starlark flag:
--incompatible_string_join_requires_strings, see: [1] for
more details.

[1] https://github.com/bazelbuild/bazel/issues/7802

Bug: Issue 10930
Change-Id: I058ba29a006e0af665830f3408e82cef4cbb1660

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