[OpenMP] OpenMP runtime test bug49334 sporadically hangs on AMDGPU

[jhuber6]

The test openmp/libomptarget/test/offloading/bug49334.cpp was re-enabled recently and has caused sporadic hangs on the AMDGPU buildbots. This test should be disabled until we can confirm that it doesn't cause the bots to timeout after 20 minutes.

[llvmbot]

@llvm/issue-subscribers-openmp