cmd/go: return an early error from queryImport when in vendor mode
The current behavior for -mod=vendor is to let QueryPackages run and
fail from queryImport: "cannot query module due to -mod=vendor".
This has the side effect of allowing "go: finding module for package"
to be printed to stderr. Instead of this, return an error before
running QueryPackages.
Fixes #58417
Change-Id: Idc0ed33d1dd1bd185348da3a18ba8eb2dd225909
GitHub-Last-Rev:
dd09deec0afecabd1bffc34cfe66db0a8c124fd9
GitHub-Pull-Request: golang/go#58471
Reviewed-on: https://go-review.googlesource.com/c/go/+/467517
Run-TryBot: Bryan Mills <bcmills@google.com>
Auto-Submit: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>