Remove stale dependency on dx.

It causes trouble if we try to switch test builds to "unbundled" mode
(in the Soong sense, i.e. a build not intended to create any system
images), because dx is disabled there.

Test: rm -rf out && art/test/testrunner/run_build_test_target.py art-linux-bionic-x64
Test: m nothing
Test: art/tools/buildbot-build.sh
Bug: 157549171
Change-Id: I500e5e6cf2b749e12288fd22efc7bfb79c76dfd7
1 file changed