cmd/go: report all loading errors in tests as "setup failed"
Currently, under *most* circumstances, if there's a package loading
error during "go test", that will get reported as a "FAIL p [setup
failed]" or "FAIL p [build failed] message and won't prevent running
unaffected test packages.
However, if there's a loading error from a non-test file in a package
listed directly on the "go test" command line, that gets reported as
an immediate fatal error, without any "FAIL" line, and without
attempting to run other tests listed on the command line. Likewise,
certain early build errors (like a package containing no Go files) are
currently immediately fatal rather than reporting a test failure.
Fix this by eliminating the check that causes that immediate failure.
This causes one minor follow-up problem: since
load.TestPackagesAndErrors was never passed a top-level package with
an error before, it doesn't currently propagate such an error to the
packages it synthesizes (even though it will propagate errors in
imported packages). Fix this by copying the error from the top-level
package into the synthesized test package while we're copying
everything else.
For #62067.
Change-Id: Icd563a3d9912256b53afd998050995e5260ebe5d
Reviewed-on: https://go-review.googlesource.com/c/go/+/558637 Reviewed-by: Russ Cox <rsc@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Sam Thanawalla <samthanawalla@google.com>