[rram_ctrl,dv] Connect rram_test_analog_io to something meaningful in rram_ctrl tb

Currently tied to a constant (assign (pull1, pull0) rram_test_analog = 1'b0;) instead of being driven/monitored meaningfully.

Start in the rram_ctrl testbench and trace rram_test_analog_io from its current constant assignment. Determine the intended meaningful driver or monitor for this signal, replace the constant connection, and verify the relevant rram_ctrl DV checks.

Written by the indexing model from the issue text.