This is a followup to https://reviews.freebsd.org/D20570 and depends on https://reviews.freebsd.org/D20735
Convert remaining 110 ports that use explicit BUILD_DEPENDS/RUN_DEPENDS on lang/go to USES=go.
The proposed change is deliberately minimal and only affects _DEPENDS/USES declarations, leaving all build/install targets in place (even if they are now redundant with USES=go).
Tested with poudiere bulk of 258 Go ports that are currently in the ports tree.