Use provided stub_shebang when building with --build_python_zip

[stdbug]

Use stub_shebang when building with --build_python_zip. Escapes single quotes within stub_shebang before passing it to echo

#8685

Tests (Debian 10):
$ bazelisk test //src/test/java/com/google/devtools/build/lib/rules/python/...:all
$ bazel test //src/test/java/com/google/devtools/build/lib/rules/python/...:all

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[stdbug]

@googlebot I signed it!

[google-cla]

We found a Contributor License Agreement for you (the sender of this pull request), but were unable to find agreements for all the commit author(s) or Co-authors. If you authored these, maybe you used a different email address in the git commits than was used to sign the CLA (login here to double check)? If these were authored by someone else, then they will need to sign a CLA as well, and confirm that they're okay with these being contributed to Google.
In order to pass this check, please resolve this problem and then comment @googlebot I fixed it.. If the bot doesn't comment, it means it doesn't think anything has changed.

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[stdbug]

Will reopen with signed user commits