Modify the logic for checking a csr_comb coverpoint hit

[Priyansh Rathi]

Currently, the coverpoints defined in the csr_comb node are evaluated for every instruction. But these coverpoints are not bound to an instruction and may evaluate to true over multiple instructions. Therefore, such coverpoints must instead be evaluated only when a CSR update is seen in the Sail log. And for this to work, the architectural state must be updated before evaluating the coverpoints. The DPR logic will also need to be modified accordingly to handle signature updates for such coverpoints.