devel/tinygo: Restrict to Go 1.25 and mark BROKEN

This port has not been updated in years, and the current port version is
incompatible with Go 1.26+. Go 1.26 will become the minimum supported Go
version very soon.

Unless someone adopts this port (the fact that it's so stale suggests
that interest is probably quite low) this port should exit the stage
when Go 1.25 does.

PR: 297237