sweet: wrap errors where possible

Currently Sweet doesn't wrap errors at all. Make that the default.

This makes it hard to check for certain types of errors before exiting
and printing more information.

[git-generate]
cd sweet
grep -R "%v" cmd/ cli/ common/ harnesses/ generators/ | grep "fmt\.Errorf" | cut -f 1 -d ":" | uniq | xargs sed -i 's/\(Errorf[^%]*\)%v/\1%w/g'

Change-Id: I6fdef3940738870ec8d7a41735fd7eb87dc7ea1b
Reviewed-on: https://go-review.googlesource.com/c/benchmarks/+/383535
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Pratt <mpratt@google.com>
8 files changed