[release/8.0-staging] [Test Only] Fix BuildChainCustomTrustStore test

Author: github-actions[bot]

src/libraries/System.Security.Cryptography/tests/X509Certificates/ChainTests.cs

@@ -344,6 +344,8 @@ public static void BuildChainCustomTrustStore(
                 chainTest.ChainPolicy.TrustMode = X509ChainTrustMode.CustomRootTrust;
                 chainTest.ChainPolicy.ExtraStore.Add(issuerCert);
 
+                X509ChainStatusFlags allowedFlags = X509ChainStatusFlags.NoError;
+
                 switch (testArguments)
                 {
                     case BuildChainCustomTrustStoreTestArguments.TrustedIntermediateUntrustedRoot:
@@ -361,14 +363,21 @@ public static void BuildChainCustomTrustStore(
                         chainHolder.DisposeChainElements();
                         chainTest.ChainPolicy.CustomTrustStore.Remove(rootCert);
                         chainTest.ChainPolicy.TrustMode = X509ChainTrustMode.System;
+                        chainTest.ChainPolicy.VerificationFlags = X509VerificationFlags.AllowUnknownCertificateAuthority;
+                        chainTest.ChainPolicy.ExtraStore.Add(rootCert);
+                        allowedFlags |= X509ChainStatusFlags.UntrustedRoot;
                         break;
                     default:
                         throw new InvalidDataException();
                 }
 
                 Assert.Equal(chainBuildsSuccessfully, chainTest.Build(endCert));
                 Assert.Equal(3, chainTest.ChainElements.Count);
-                Assert.Equal(chainFlags, chainTest.AllStatusFlags());
+
+                X509ChainStatusFlags actualFlags = chainTest.AllStatusFlags();
+                actualFlags &= ~allowedFlags;
+
+                Assert.Equal(chainFlags, actualFlags);
             }
         }