Dave Navarro shared a cryptic message on Instagram following his onstage confrontation with singer Perry Farrell, and fans are already speculating that the guitarist has quit Jane’s Addiction. On Friday, Sept. 13, things got explosive between the bandmates during a performance in Boston. Videos show that tension seemed to bubble up during the band’s rendition of “Mountain Song,” when Farrell could be seen shouting at Navarro. The hostility boiled over two songs later, as Jane’s Addiction was rocking through “Ocean Size.” A clearly agitated Farrell confronted Navarro onstage, shoving the guitar…