How much does icing and taking Advil (ibuprofen) reduce recovery time for minor muscle strains?

Not much, but < pain. Advil (ibuprofen) and similar anti-inflammatory medications may not actually reduce recovery time significantly. They do reduce pain and swelling which may indirectly allow rehabilitation and recovery to move forward at standard healthy pace.
Helps symptoms. The ice and Advil (ibuprofen) may not reduce the recovery time, but they reduce the discomfort while you are waiting for it to resolve.