CertVerifyProcMacTest.MacKeychainReordering is being disabled because the certificate it uses in the test chains to a Symantec root which is being distrusted in  crbug.com/796230 .

This test was originally introduced in https://codereview.chromium.org/2362533002. I don't know the details of the original bug well enough to find a replacement certificate to use in this test.

If all that's needed is a cert (with chain) where the root CA has a cert for that name/key where the signature algorithm uses SHA-1, then https://crt.sh/?id=595081092 chaining to https://crt.sh/?id=88 might be a suitable replacment.