Create reform for TCJA "current policy" extension

[MaxGhenis]

Many analysts are comparing reforms against a baseline that assumes TCJA extension. We should make a reform that does this. The main time-consuming part will be correctly applying inflation adjustments. Might be simplest to do that by locally deleting values of parameters affected by TCJA from 2026 on, then extract the uprated values and write them to a reform.

Unless there might be a way to apply uprating to apply uprating from parametric reforms? @nikhilwoodruff?