cmd/go/internal/modload: eliminate QueryPackage
    
    QueryPackage was a wrapper around QueryPattern with extra validation,
    called only once from within the same package. Most of that validation
    was already performed much earlier, in (*loader).Load. Inline the
    remaining validation and remove the needless indirection.
    
    For #36460
    
    Change-Id: I108a01d416197db8f886889554e07b29f0c37f3f
    Reviewed-on: https://go-review.googlesource.com/c/go/+/256057
    Trust: Bryan C. Mills <bcmills@google.com>
    Trust: Jay Conrod <jayconrod@google.com>
    Run-TryBot: Bryan C. Mills <bcmills@google.com>
    TryBot-Result: Go Bot <gobot@golang.org>
    Reviewed-by: Michael Matloob <matloob@golang.org>
    Reviewed-by: Jay Conrod <jayconrod@google.com>