Revert "Disable running run-test with linux_bionic"

The build_linux_bionic_tests.sh script was using incorrect environment
variables causing it to fail to build all required libraries when run
on the bots.

Reason for revert: Fixed issue with running linux_bionic run-tests on
                   the bots.

This reverts commit 1d77a70b.

Test: cd <android-root>;  # don't do envsetup or lunch
      ./art/test/testrunner/run_build_test_target.py -j80 art-linux-bionic-x64

Bug: 119673278
Bug: 119687007

Change-Id: I6f484d0d2e2accbfab6bd90c510915d5e2eeb64d