Bug[hefloat/bootstrapping]: bootstrapping.NewEvaluator modifies bootstrapping.Parameters

[Pro7ech]

Instantiating a bootstrapping.Evaluator modifies the bootstrapping.Parameters template that is given as input. Reusing the same bootstrapping.Parameters to instantiate a second bootstrapping.Evaluator produces a bootstrapping.Evaluator that has incorrect internal initialization of the plaintext constants.

This bug is caused by

1. The bootstrapping.Parameters having some field that are pointer to values
2. The bootstrapping.Parameters being copied in the bootstrapping.Evaluator without allocating new pointers for the said values
3. The said values then being modified by the bootstrapping.Evaluator