cmd/go/internal/load: make check for path in import error more robust
When producing an ImportPathError from ImportErrorf, we check to see
whether the error string contains the path for the error. The issue is
that we were checking for the exact path string when sometimes the
string is quoted when the error is constructed, and the escaping in the
quote may not match the path string. Check for both the path string, and
the quoted path string.
Fixes #68737
Change-Id: I01bf4e495056e929570bc11bc1f2000ce6d2802b
Reviewed-on: https://go-review.googlesource.com/c/go/+/603475
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Sam Thanawalla <samthanawalla@google.com>