crypto/x509: return typed verification errors on macOS

crypto/x509: return typed verification errors on macOS

On macOS return the error code from SecTrustEvaluateWithError, and use
it to create typed errors that can be returned from Verify.

Fixes #56891

Change-Id: Ib597ce202abb60702f730e75da583894422e4c14
Reviewed-on: https://go-review.googlesource.com/c/go/+/452620
Run-TryBot: Roland Shoemaker <roland@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>