Revert "Call jit decomposition in VariableType to increase forward AD coverage (#84151)"
This reverts commit 42d99e6f196233627a28b8e9efb26a0a166fa370.
Reverted https://github.com/pytorch/pytorch/pull/84151 on behalf of https://github.com/malfet due to Regressed test_jvpvjp_nn_functional_layer_norm_cuda_float32, see https://hud.pytorch.org/pytorch/pytorch/commit/42d99e6f196233627a28b8e9efb26a0a166fa370
