Revert "[RUST][CI] Add rust frontend tests in Jenkins"

[tqchen]

Reverts #2375

[tqchen]

@ehsanmok Sorry I have to revert this PR because the new outrage it brings. After a second thought, I do think that it is possible to do rust testing in the build cpu stage. The build itself should have already provide build/lib_tvm_runtime.so . So if there is something wrong, it is unlikely has things to do with the pack library. You do not need to unpack libraries because the library is getting build in the current stage

[ehsanmok]

Very strange! I don't know how then. I've already tried the normal frontend build at least 3 times and the CI fails due to not finding libtvm_runtime.so and thought the process should be the same as java for example. The .so is not found in LD_LIBRARY_PATH

[tqchen]

I see, the .so is indeed not in LD_LIBRARY_PATH and they reside in root/build by default, maybe a simple change is to add root/build to LD_LIBRARY_PATH