Remove tradefed-contrib module

tradefed-contrib module was added as tradefed_test prerequisite for
historical reason. The code that was needed was moved to Atest's own jar
file to accomendate TF prebuit process. Removing it to prevent Atest
Bazel mode failure in branches with TF prebuilts.

Bug: 232552492
Test: atest bazel_mode_test
Test: atest atest_unittests
Change-Id: Ic796bbeec6f2abe8b170dff3c48039f377e29826
Merged-In: I5f4c77bcb8f1bb94e93fa0965f2a55c75b3c0bf0
Merged-In: Ia92e3efae0d3d37386b6f673642e378cd7283a37
Merged-In: Ie27c1dd4f36af69eef9c05e12e32b614e62c2918
Merged-In: Ie42f649c907ed4dcf0557c1bbb73ea6565654756
1 file changed