Exclude certain operators from injection

[nniranjhana]

Injecting operators like Shape should be excluded. Accuracy reported might be wrong in these cases, as number of elements changes.

Also, curate a list of operators which just get values from the tf object, and/or not involved in computation and exclude them for fault injection.

Choosing "ALL" in the Ops configuration file will then work better.

[nniranjhana]

This is a list of operators I think we should exclude.
If you differ from this list, please unmark and state why. Alternatively, do add more too:

• tf.shape
• tf.rank
• tf.one_hot

Should operators like tf.expand_dims and tf.reshape be excluded? Their outputs are not a dimension, but tensors, so it would be sane to inject faults into them. But does injecting faults into these operators make sense?