security/snowflake-tor: fix build on riscv64

Bump dependencies to version new enough to support riscv64-freebsd:

    golang.org/x/{mod,net,text,tools,sys}
    github.com/templexxx/cpu

While we are at it, only strip if requested.

Sponsored by:	Berliner Linux User Group e.V.
Approved by:	portmgr (build fix blanket)