cmd/dist: refactor rtPreFunc to print skips in only one place
Currently, all uses of rtPreFunc are to print a message and skip a
test. When we move to JSON, the logic to just "print a message" is
going to be more complicated, so refactor this so the function returns
the skip message and we print it in just one place. We also rename the
option to rtSkipFunc to better represent what we use it for.
For #37486.
Change-Id: Ibd537064fa646a956a1c0f85a5d8c6febd098dde
Reviewed-on: https://go-review.googlesource.com/c/go/+/495856
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>